[CaptainGizmo]

Captain,
Any recommendation as to how many of each type to order? Both for a revamp and to have some spares??

Unfortunately, what my coach has would differ from your's quite a bit.  I stopped counted, to be honest.

Instead, I just made and inventory of each "grouping" of fittings, looking at which ones I could get to right away.

For my coach, the biggest gathering of fittings needing attention were:
 - the compressor bay...BE SURE YOU TEST WHILE RUNNING since some of the lines aren't under pressure until then.
 - the rear air bay with the doubler, manifold, shop air fitting, backup charger...over 2 dozen fittings in that neck-breaking compartment!
 - air tanks and brake manifolds under coach!

and misc areas that have leaked (and easy to get to as well)
 - the BODE door mechanism
 - engine compressor
 - air-ride seat

Then, I ordered pretty much 2 of each type/size so I'd have an emergency fitting for the ones I haven''t replaced.

In total, I ordered over 2 dozen fittings. If you'd like to see my actual receipts, just drop me a PM.

In terms of the suggestion to use a Street Ell, I'm in the camp of the LESS FITTINGS I have, the better off I am.  Therefore, I use a single brass 90º when possible.  And, anytime I see a reducer, I first try to find a single fitting that covers the reduction, rather than stepping it down a couple times.