Using rings is an interesting idea... I've been looking at this
Ages Walkthrough (scroll almost to the bottom to find the rings section). It seems as though several of these rings could be useful:
a. Whimsical Ring, for Tompa's reasons. I'm not so sure, though, that the critical hits work on bosses.
b. Power Ring lvl2, increases sword damage
c. Charge ring/Spin ring, allows for better use of the spin attack
It might even be useful to grab the upgraded ring box, but remember that for each ring, you have to find and manipulate Maple, then go back to Vasu and have it appraised for 20 rupees. I seriously doubt getting more that one ring is useful. So, we should pick the most useful ring of those above.
Although, I'm even starting to wonder if getting a single ring is worth the time. It seems to me that the combined time of manipulating a specific ring out of Maple, running back to Vasu and listening to his opening talk, then getting the ring appraised makes for too much wasted time. You could probably get the potion and the ring from Maple at the same time, but good luck trying to manipulate that! I would estimate that getting back to Vasu, after getting the ring from the closest Maple spot, would be a detour of about 30 seconds.
Of course, you could also just use a password to get all 64 rings, but that's probably cheating :)