Does the Ventum series do the same thing as the Flow series, where it's ejecting the gasses radially to constantly tighten the can with each shot? If so, I would highly recommend a reverse thread setup, like the Huxwrx or Xeno systems and to Rockset the muzzle device on. It's either that, or you're going to be really hoping the Rockset doesn't come loose when taking the can off.
I really like the Huxwrx QD system on the Flow 556k, but the one downside to the Huxwrx system is weight. Their HUB adapter is chunky at 4 oz, plus 3.3 oz for the Flow flash hider. It isn't bad for the Flow series, since the adapter is built into the can (my total Flow 556k system weight when brand new was 14.95 oz per my scale), but the Ventum 556 is already a bit heavy at 15.2 oz on its own (I'm assuming this is with the direct thread adapter). 15.2 oz + 4 oz + 3.3 oz - 2.5 oz (est for the direct thread adapter) = 20 oz total system weight. A Ventum 556 with Xeno Xero would have a total system weight of 16.5 oz and a Rearden Minimalist setup would be 16.4 oz total system weight.