I have several teams that are young and undersized at PF/C positions in both D1 and D2 levels.  Playing Man is my defense.  Not sure how to position team to help rebound, and to not kill myself out front with my guards.  Does anybody have an idea of the effect of -1 versus -2 on assisting, and would you ever go -3?

I go +5, +4, +3, +2, +1, 0, -1, -2, -3, -4, -5

It depends on my team each season and what team I am playing.   Don't ever rule out any of your options.

If you are playing a M2M, I would have little to no reservations about going all the way to -5, depending on the opponent.

Am I correct that the more minus you go, you are dropping your guards lower in the key as an assist to rebounding?

I think of it more in terms of blocking passing lanes and compensating for quickness in your opponents guards. Any increase in your guards rebounding is more of a side effect than a primary reason for dropping back.

i think of it in these relatively simple terms now:
- increases 2 pt defense 
- hurts 3 pt defense
- increases rebounding
- increases fouls

opposite for +... although im not sure the extend is really the same. like, its not symmetrical around 0, i don't think, like a +5 isn't going to be as much less fouls as a 0, as a 0 is compared to -5. im not even really sure you keep getting benefit all the way up. ive wondered the same about rebounding.

To piggy back a bit on this, in my experience a -5 will be much more foul prone than -4. Thus, w/ my M2M, I will never begin a game as a -5. If I am up against a team that hardly ever shoots a 3, I'll go to -4.