We've pulled many GT Superchargers. (A prerequisite to installing a pulley/tune which is likely one of the most popular GT mods in GT-land.) Some look like the pic that sinovac posted, some are fairly dry and most are in-between.
But let's look at the that catch-can "results" referenced in that older thread. In that picture... it sure doesn't look like 1/3 cup, but let's pretend that it is. What horrors are we really subjecting the engine to?
Author of that thread "Caught" 1/3 of a cup across 5000 miles
1 cup = 48 teaspoons; 1/3 cup = 16 teaspoons
1 Teaspoon = ~100 drops; 16 teaspoons = 1600 drops
1600 drops across 5000 miles = 1600/5000 = 0.32 drops per mile (oh the tragedy!)
Assumption: GT is averaging 16 mpg
1 mile = 1/16 gallons of gasoline is consumed
128 ounces per gallon
1/16 gallon = 8 ounces
8 ounces = 48 teaspoons
1 teaspoon = 100 drops
Conclusion: GT @ 16 mpg (avg) burns approximately 4800 "drops" of gasoline per mile
While the engine is consuming 4800 drops of fuel/mile, the catch can "saved" the engine from having to ingest 0.32 drops of blow-by.
Viewed differently, had this been forced down the throat of the engine, compared to fuel being consumed, it represents 0.32/4800 = .0000666; or .0067%
Not all that compelling to me to spend money to solve a problem that simply doesn't exist.
(I think the argument changes when you talk about bigger boost from Whipples or turbos as the added pressures will definitely increase blow-by and it *may* get it into the range where you want to be pro-active about it.)