I run a JP Enterprises PSC11(20" barrel) with adjustable gas block and have experienced no issues with gas/crap in my face although this is a little longer than what you are looking at doing..... Hope this helps.
I can vouch for the Spectre II, very quiet can although seems a little heavy for a .22 can? As for suppression I have no other equipment that I can compare it too but seems very quiet to my ear.
Couldnt agree more with the previous statements. Will be a lifetime JP customer as a direct result of the stellar products and the above and beyond customer service experiences. Ben is truly a great guy to deal with.