2 of 2 erased a wrong "flat" and put in bar numbers.

Is this a helpful way to think about Coltrane Substitution?

More specifically, is it harmful? From the ii-V-I I could backtrack from the I and suss out the flatVImaj7 and the IIImaj7, but what about:

Bar 1 ii-up a half step to a dominant -

Bar2 down a fourth to a maj7 - up a minor third to a dominant -

Bar 3 down a fourth to a maj7 - up a minor third to a dominant - <-- this is the original V

Bar 4 I