OK here is what I using CEP.
First of all, I suggest you join each source, then they will be synched. Then cut out a fairly short section that contains something representative - vocals and jams fom one of the louder regions from both sources. Otherwise this will take too long to process to really be able to compare much.
Also, unless the L/R balance of an individual source seems off (and if I remember, both of these were reasonably close) I don't worry so much about stuff like normalizing each source to some value. Instead I just mix them as is and listen and make sure I keep track of it all so I can reproduce everything I did later. Your call on how you like to proceed.
So...
Step-By-Step: (And keep in mind I am no CEP whiz, so if someone can improve on this, please do).
Step 1) Decode the Mid-Side ADK source first. (Obviously this requires the most work).
The left channel is the Mid Cardioid. The Right channel is the side Figure 8.
Mid + Side = new Left Channel
Mid - Side = new Right Channel
To Decode the M/S source into L/R in CEP Select Effects > Channel Mixer. There is a preset for Mid-Side to L/R. Select that option.
CEP M/S decoding is a little confusing, because they don't give things in "ratios". When you first select the preset you will see 4 sliders. The new Left will default to 100L, 100R. The new Right will default to 100L, -100R.
The CEP documentation on this sucks, but from what I can piece together, I *think* the following is true, not absolutely positive:
This default is equivalent to a 50:50 Mid-Side decode. Decoding does not change the total signal (although I think this might be based on keeping something else constant like RMS so you may see some changes in the final dB levels.)
According to CEP help using channel mixer functions should not add gain, but I usually see a bump of maybe 2 or so dB in the final L/R channels. For 24 bit the final decode will still have lotsa head room to work with later.
If you set the new Left channel to 100L, 0R, new Right Channel to 100L, 0R, the result will be a "mono", or more correctly, 100% mid (cardioid only) L/R.
If you set the new Left channel to 0L, 100R, and the new Right channel to 0L, -100R the result will be a 100% side (Figure 8 only) L/R.
Anything else is somewhere between.
To increase the Mid:Side, I would suggest you leave both left channels at 100L for Left, and start decreasing the Right from between 0-100R for the new Left channel and -100-0R for the new Right channel.
Ditto for decreasing Mid:Side. Leave right channels at 100R, and -100R for new Left and new Right and start decreasing the Left from 0-100L for both new Left and new Right.
In the first case you are actually leaving the Mid at "full", but decreasing the Side, which results in higher Mid:Side ratio. In the second case you are leaving the Side at "full" and decreasing the Mid which results in a lower Mid:Side ratio.
(Again this is a little confusing because CEP does not use the typical "ratio".)
One thing for sure: even though CEP will let you do it, do not go outside these bounds:
Left for both new Left and Right: 0-100L.
If you go below 0, it does not "reduce" the Mid anymore, it starts inverting it's polarity.
Same is true for Right for new Left and Right except here you have plus and minus so:
New Left: Keep new Right between 0-100R, or you are inverting.
New Right: Keep new Right between -100-0R, or you are inverting.
This will make a lot more sense once you start working with it. Play around starting at extremes and working inward. Once you decide on a ratio, you may want to tweak the final L/R a little if needed. I suggest you don't bump it up because the next step is "additive".
Step 2) Start merging the two sources.
Again it's better to be working with a short section because you may want to go back and try a different M/S ratio after you try merging.
In CEP, open the Gefell source wav section that matches the ADK section. Of course since it is a normal L/R stereo source you don't need to decode. If you feel the need again, tweak L/R if you want. You should now have both sources open.
Percentages will not help you here. As far as I know Multi-Track view can only be used in dB format. Again not a CEP whiz. If you decide that you want to bump gain first on both sources, you'll need to do this subtractively. I am assuming original 24bit sources with low intrinsic gain.
In menu select View, Multitrack view. Empty multi tracks appear. Put the mouse in the Track 1 window. Be careful not to click - it will move the cursor. With the mouse inside Track 1, right click, then a drop down appears, select "Insert" and you will see your two open wavs. Select the ADK source and it will be copied into Track 1. Repeat for Track 2 using the Gefell source.
Now here is the tricky part. As far as I know there is no way to start mixing with specified ratio - I only know how to mix down all tracks. For the typical way I usually run the 722 you probably have maybe 8dB headroom to work with. You can control the final mix ratio by setting the volume on each individual track.
This Mid-Side source is not very good, definitely not a primary source. So you will almost for sure want more of the Gefell. Again this process is additive.
Beside Track 1 you will see a box that says V0. Right click on that. For starters bump that up to 2.5 dB, assuming that is the ADK source.
Beside Track 2 do the same except bump that to maybe 5 dB, assuming that is the Gefell source.
Now put the cursor in Track 3 (empty) and right click. This time select "Mix Down To Track (Bounce) and then "All Waves".
The result in Track 3 will be Track 1 at whatever gain + Track 2 at whatever gain + 7.5dB additional gain added to the additive gains already present, but with 2.5 dB added to the ADK source and 5dB added to the Gefell source. Gives you roughly a 75% Gefell/25% ADK mix. Listen, save and then purge Track 3 (or not), repeat.
If you want to try mixes without saving and clearing Track 3 every time then make sure when you mix all waves into, e.g. Track 4, you also set the volume in Track 3 down to -infinity. This will allow you to keep the Track 3 mix without anything being added from it to your next attempt.
Sorry this is not very exact. Only attempted the 4 mic mixes a few times, and not in good venues.
And as far as post - I am a taper, not a producer.
If anybody knows a better way, please post.