[Freon]

Some sort of crank case ventilation is required for the engine to operate properly. There's not much getting around it. You can try to filter it as best you can. You should definitely never block off a crank case vent. The pressure will just build and find a way out, probably not in any convenient way for you as the owner.

Older cars would vent straight to atmosphere or into the exhaust, but those are not solutions that I feel are worth looking into.

One suggestion is to place the catch can in a place with fresh air, so it stays significantly cooler than the air and rest of the engine bay. The colder it is, the better it will promote condensation.

The ebay can you linked doesn't seem to be much more than an empty can rather than have any features that would encourage oil and air separation.

I can't find great pictures of the Riss Racing, but found one showing it installed directly above the turbos, which is about as bad as you can get.