Yellowfin on 20lb braid, yeah, should be easy enough to do, what line cap do those reels have, around 350-400m? Piece of cake mate really.
I would beef up the hooks on the storm anchovies though, they are pretty soft, especially for a yellowfin. Swap the split rings for something a little more substantial and a bootier hook. I got a few big skippies here using exactly those lures on a 15lb TiCA Taurus 4000, and a nice yellowfin of around 10-12kgs or so in the sollies, that was about 3-4 years ago though when I was playing with those SPs when Kilwell still had the agency for the Storm gear.
Dammit, I can't put on the pics, as they are on the home comp, not this one I have at the beach.
But sure, no reason why that gear shouldn't be able to handle a reasonable fish. Must say, I was using a kilwell live fibre custom made rod with my TiCA Taurus on the tunas, so don't know how a lesser rod would perform. If you took it easy then I suppose it could hold up to it.
Good hunting though... I went for a big shad (sorry, I think they call them pogies these days now) once when on a meatball off whakatane, thought it'd be neat to get a tuna on one for a mag story (looking as I was in those days for anything different to write about), but I got inhaled by a bloody great blue shark instead... so much for that idea! :-) Teeeerrrrr...riffic! Decided not to play that silly game no more and went back to livies, and got the yellowfin that way. Hell, that must've been... geez, last century! Hells teeth, makes me feel old! :-)
cheers, Stu.