Barry,
When you're discussing measures 15 and 16 (the Ebm7-Ab7-Dm7-G7), you discuss the desirability of sticking to the natural extensions on the Ab7 during this chromatic sequence. I'm wondering about the advisability of using or avoiding tritone subs for Ab7 and G7 in this. They're easy moves to make, and to me it sounds ok (and perhaps individual taste is the whole point), but do you think those are reasonable or do you think they detract from the clarity of the intended progression. I'm assuming that it's less critical when these tritones aren't the melody notes. Just looking for ways to vary the sound a bit during solos/comps.
I'm not entirely sure what you're asking but the chromatic II-V is an important part of that cadence to the I chord. I know many musicians who whenever the want the altered dominant sound will think of the tritone instead. Hope that helps
Barry