As mentioned, today's spinning reels can apply the same pressure as what your 50W's are set for now.

Frankly IMO tuna have a much bigger problem then the release mortality from spinning gear...overfishing overseas. This needs to be fixed before releasing a few fish with trebles on spinning rods is going to have any significant effect on the biomass of the species.

LOL KR - yes, the game would've been a bit shorter if i was on the rod the whole time - got a week or so to go before my wrist is completely healed. But, i was on it for the end game. with the spinning gear, we circled the fish and gained line, got him to the boat quicker. we could've hooked up all day out there - i'll let you know when we're going next

50vsw's put down 30lbs max strike drag and the moon is limit for max drag.

Avet T-Rex 50's will go up to 50ish lbs strike and over 100 max.

I don't think even the Accurate twin spin can come up to those numbers at max... But I could be wrong.

I think the big stella and saltiga can put a max of 65# of drag, which is a lot for a stand up. But as I casually said..." apply the same pressure as what your 50W's are set for now" Most reels are not anywhere near set to apply the max. Bottom line, a friend took a 220# Bigeye on one in less than an hour and a half. Its do-able for anything short of a real big giant.
IMO, the problem is you need to use braid to get the capacity. Fishing big fish with braid and high drags...you tend to loose more fish. You really can't put enough top shot of mono on a spinner so you really are in a pickle about putting alot of drag on. (This is just from my experience) So most guys I know put plenty of drag (but not maxed out)and end up chasing the fish down.

(I want to catch a nice wahoo on one...have you ever seen those things swim? JeeezzzUS! talk about a burst of speed!)