It seems like a lot of this advice thus far is all over the map. I don't own a 9100 anymore, but assuming that it doesn't function radically differently from any other preamp, I don't know why you would turn it up to "max" and then take levels from the DR-07. The preamp itself can overload, and I would think, would, at high SPL if its gain is turned all the way up.
As I understand it:
You don't want the DR-07 determining the levels - you don't want the DR-07's internal pres doing any work, because (presumably) they aren't as good as the 9100s - that's after all why you bought it, right?
Therefore, you want the DR-07 at "unity" - at whatever level its preamp is essentially neutral, neither providing nor reducing gain - and then you want to set your levels by varying the gain on the 9100. On my M10 I leave the level knob at ~5 and adjust the gain off of the littlebox. When I had a CA9100>R-09HR, I left the R-09HR at "40" and varied the gain on the 9100.
If Chris has a different way of operating his gear, it's of course his gear to comment on, but some of what's being said here just doesn't make sense to me.