Have you had it for awhile?
I'd suggest considering what line you've found that matches it best for you, and take that line into the RIO recommendations. If your line is a RIO it's easy. If not, either you or someone hear can probably find the grain weight of the head for comparison. If you find that your line is on the lighter end, then you'd probably be happiest with the lighter recommendation from RIO. If you find that you like lines that load more deeply, then probably the heavier recommendation from RIO. Good luck!