Ok, the long wait has begun finally for my Saker.
I want to know about piston systems that are not gassy, or as gassy at the ejection port while suppressed.

I would assume it would have to be some type of long stroke with a rod. What's out there?

I can always use a Stag upper to get it away from me, but would mess up any rightys that shot it.

I believe PWS uses a long stroke piston system for its ARs. Most, if not all, of the other manufacturers use short stroke pistons for ARs.

I have a 14.5" piston LWRC upper. I always shoot it suppressed, so in theory is may be over gassed. I don't have any issues with the LWRC. Actually, I've never seen gassing issues with other piston ARs, either.

I've had my YHM ULT can for a few years now and run it on everything:
Barret Rec7 Flyweight 16", in reduced gas position, very little gas to face after mag dump.
Homebuilt 12.5" 6.8 SPC with Superlative Arms piston kit, very little gas to face.
Homebuilt 16" 6.8 SPC with Adams Arms piston kit, very little gas to face.
Homebuilt 16" 5.56 with Adams Arms piston kit, very little gas to face.
As a point of reference, my Aero Preceision 8" DI SBR 300 BO was unbearable after 3 shots. I added a Superlative arms DI gas block and now I can get to 20 rounds before taking a break.
For fun I just finished building a DI lefty with a Sionics 11.5", with a SA gas block. Awesome shooter, and the ejection port on the correct side is great!
I'm a big piston believer for lefty suppressed shooting.