Well, it all depends on who is your +1 and how valuable are the other players. Clearly, if the +1 is a big man I think it wouldn't make sense pushing him more to the outside, especially if you have 2 guards composing the box then.
On the other hand, it's pretty obvious that, if the +1 is going to be a guard without a high level of ID...it would be the opposite. The limitation of a excellent interior scorer will be very little if the m2m defence is assigned to a low ID player.
Your idea anyway is not wrong, I mean, it all depends on players. Let's say your best defender is a guard (for example PG) and all the other players remaining possess good ID...in that scenario it could make sense playing an inside box to use the box to defend the interior. In a different situation, as for example if your best defender is your PF and/or your guards don't have ID, I wouldn't consider this a good option. You'd lose your best interior defender on a m2m defence on a outside player...and you'd ask to defend the inside to a couple of guards with average/low ID.
But that's an interesting point!
I would love to run some tests with a well built inside box against LI, unfortunately right now I'm in rebuilding mode and I'm not in the position to do that.
I have little datas regarding rebounding. The ratings are not too much different compared to a m2m with the same lineup, maybe slightly better but, at the time, I was focusing on different aspects.