Makes perfect sense. Great little cycle that you have outlined here. I like the addition of a moderate dose of NPP. I would prefer to use a longer acting test for a 16 wk cycle, but thats just an opinion. The less oil I can use to reach the MG's I want to use, the better. None the less, prop will work out just fine. Even though this isn't going to be a highly estrogenic cycle, I would still use a little adex. Not much, but enough to keep some of your test from converting to estrogen and to get a little protection from the Dbol.
Looks like a great plan. Just remember that a "lean mass cycle" is all about diet. If you want to stay lean and grow, keep the food clean and see how much you can eat without getting overly fat. I'd throw in a little cardio a few times a wk. Not much, but enough to keep you leaner and keep you hungry.
I've had some good expereince with Geneza NPP from Naps. I highly recommend it