Want opinions on the best way to keep tracks organized in the arranger. I'm sure it will differ upon personality but want to consider:

What's best for the mastering engineer
What's best to optimise for sound quality
What's best to optimise for creativity
What keeps things less mentally confusing

I always keep my kick seperate
I roll drums into rhythmically associated groups in one track... in other words one MIDI track with a sampler with key assignments for each drum.
I keep leads and pads seperate from eachother.
FX I keep seperate.

Drums seem easy to group in one track together because rendering them as one doesn't seem like that big a deal.

But what to do with leads, pads and FX which overlap quite a bit? Can they be presented to a mastering engineer flattened? Flattened in chunks? Or kept completely seperate?