Mark - Anything over PE 2 is too much for the Ryoga in my opinion... not because of the reels ability, but rather its capacity....
I only managed to squeeze on 200 metres of YGK Ultra PE 2 which is very skinny....
If Capacity is not an issue, then PE2.5 would be no problem, but you'll only get 150 to 180 metres on there...
If you looking at Jerry Brown, I would rather look at the 20lb, the 50lb in my opinion is waaaaay to thick for that reel...
Mine is still spooled with the YGK Ultra PE 2, but I'm down to only about 140 metres left after bust offs and such, which happen alot on that light braid, especially when its as skinny as YGK Ultra... am respooling soon and will be going with Jerry Brown in 20lb...