While only reading through a handful of responses, I will just say a few things:
I'm certain that your taper friend knows better than most what your needs are since you speak to him about what you want and he is aware of the music and venues you play. That said, I know he didn't suggest that you use any shotgun mics at all. Yes, the Nak 300 shotguns are a good pair of shotguns, but completely unnecessary for your needs. If you were recording from the soundboard area at a fair distence away, yes, but otherwise, no. You'd need the cp-301's, I believe, which should be the cardioid capsules.
A pair or more of Nak 300 mics, depending on whether you want to mic amps on stage or record from the FOH, are a solid pair of microphones that sound a lot better than many more current offerings at a better price, because they are discontinued. They are also a very "forgiving" pair of mics that need a little less attention that many others. The battery situation sucks because they don't make those batteries anymore either, which is why he suggested to modify them for 48v phantom power, thereby eliminating the need for batteries, and taking power from the Sound Devices MixPre instead (also eliminating the need for a separate pre-amp - another piece of equipment). You can pick up a MixPre here in the Yard Sale or on ebay for a good price. I'd recommend buying through the Yard Sale from recommended sellers if you choose to go that route. Same with the microphones, whatever you choose. If you can find a pair of Nak 300's already modified for 48v, even better, as they will probably be cost effective.
Regarding the audio. As a few have pointed out, the MixPre has better pre-amps than a lot of decks out there. Sound Devices is a professional company, unlike Zoom, who tries, but in my opinion, falls way short of Sound Devices...especially their pre-amps. There are several MixPre decks and you'd get what you need based on your amount of inputs. If you only plan to use a pair of mics in front of the stage, all you need is a MixPre 3. If you think you'll want to mic monitors, amps, use in the audience, take a line out of the soundboard in addition to microphones, etc., you'd need a MixPre 6 or higher. By your friend suggesting a MixPre 6, he is most likely thinking that you'd want to grow with it instead of having to buy a deck with more inputs later if you want to do that. Again, that may have been part of your conversation with him, so he may have more insight that the rest of your recommendations.
Very quickly, to add about microphones: They are all subjective to your ear and personal taste. For example, I would not choose KM184's over 300's under any foreseeable circumstances. I've never like their sound. You might though. I've run a pair myself side by side with Nak 700's (everything else being equal) and asked the owner of the 184's which he liked better after only balancing the levels and bringing them all up to the same for comparison. He knew the mic difference immediately and said that the 700's sounded much better. He then commented that his old recordings with his old Nak 300's still hold up against the 184's he uses today. The batteries caused a lot of people to move away from the 300's. I still listen to my old 300 recordings and have no complaints. You should take the advice and listen to different recordings with different mics at the same venu, preferably from the same location with the same recording decks to get the most unbiased sound you can to judge for yourself. Your friend can help you with that too, I'm sure.
Location, location, location, as a few mentioned is of course an extremely important factor. However, and again, your taper friend knows his shit and is making suggestions already knowing you, what you play, and the type of venues you play in. Being that it's your band, you will be able to set up the mics wherever you want, providing the venue's rules don't prohibit it. At a soundboard, where you can press record and walk away is ideal in smaller venues or at outdoor shows. Having 32bit float is a plus, but any taper worth his weight in tapes knows how to set their levels. 32bit float is a relatively new option, so older tapers don't need it because they already know what they're doing. Most of them want the smaller units with 32bit float because they use them in a stealth situation, which you will not be doing. There are limiters on the decks for a reason...which is all you'd need, because either your friend will help you learn what to do or you already know to set your levels a little lower if you can't watch them and turn on the limiter. I wouldn't be concerned about that.
My suggestion for you is to read all of the comments on here and write down any specific questions you still have, need more clarification on, or are just curious about. From there, speak to your friend first and ask him those questions. Depending on the outcome, or regardless of the outcome, you can always post those specific questions, and more if more questions arise from your conversation, and post them here.