The 2nd encounter with the Super Soldiers isn't that tough.
Arm the Panzerfaust and shoot and duck @ the 1st one. Arm the Venom and do the same until both are taken out. Short bursts on the Venom are important b/c sustained firing is inaccurate and only effective at point blank; problem is they have a clear shot at you, also.
Another tactic was to use the crates as cover. Use all your Panzerfaust and then arm the Paratroop rifle. Head to the crates. Now notice that they're in a higher elevation. Use that to your advantage (?) Of course. As you'll find out, in long range the first one will use Panzerfaust then Venom. Its shots won't even hit you, not even the second one with its Tesla, Panzerfaust, or Venom. Just aim the crosshair slightly above the crates when they're in site using the crates as cover.
When they come close, head around the corner. They won't shoot unless they have a direct shot at you. Up close, again use the crates; they're huge targets. You can get a few shots in with the Paratroop rifle until they round the corner to get a clean shot at you.
Like someone said earlier, the very 1st encounter with the Uber Soldat was a pain. I found out later that it wasn't much of hassle as soon as I discovered the booth right under Deathhead's Observation booth.