On making most of available poly - as above for the DSP split.
What I do I look at the patch complexity meters and eventually move my parts to try and balance the load between the two DSPs. This can help when you are hitting marginal poly.
Also another side effect of this split is on *very* complex high unison patches where you might expect to be able to play a 4 note+ chord in theory from the specs access published - youmill find actual poly available to a single mode patch is about half what you might expect.
Think unison x 8 patches with just about everything switch on... you can sometimes just end up with a very fat mono synth and thats your lot
