Fail troll is fail. The idea is that he's healing twice his level + 4 times his Con mod each hour. For a Goliath Barbarian with maxed Con (18 + 2 Racial + 5 Levels + 5 Tome + 6 Enhancement = 36 for +13 mod), that's 53 HP an hour for 1272 HP a day.
Fail what?
I say Ring of Regeneration flat out sucks & you agree it costs to much. Then the whole blabber amount the amount of HP healed thing doesn't help you at all. Con 36 + Rapid Metabolism + Ring of Regeneration + Periapt of Wound Closure heals a whole 200HP more but costs an additional feat slot and 15,000gp. Not to mention it requires a 137,500gp tome, 36,000gp +6 enhancement time, and all five level boosts put into Constitution to pull that off.
You just dedicated a lot of build aspects towards healing a relativity minor amount of HP over what simply buying useful magic items can do but I failed? Spend one tenth of that 188,500 you've used on more belts. 25 belts = 50d8 = 225HP & 169,650gp as pocket change. With the money left over pick up a +4 tome & +6 enhance for Con. If it spends two level up points in Con the entire thing heals as much as your dedicated build but can have +3 more Con, has the option to rapid fire it's daily healing to reach max amount under a minute (vs several hours), can pick up an extra feat, and still spent less gold.
As mentioned. Ditch the ring. It is so ineffective that the inclusion of it into anything creates a negative aspect on the outcome of everything else. It's like a kidney punch before shooting the game ending free throw.
A wand lesser vigor heals 600 hp per hour topping you off in a little over 20 minutes and a wand of clw heals about 5 1/2 times these full heals will cost about 305 and 610 gp respectively. That's about 155 full heals from the faster, less efficient, core spell or 155 full heals for the price of your slow heal items after buying someone in your party a +10 UMD item which will have numerous uses over the course of the campaign.
Wands of Lesser Vigor are the default minimum standard of Min/Max healing.
You know, speaking of trolling. I don't see Regeneration listed on the ban list.
Would 1,200 for PAO to Troll for 400,000+ HP healed per day get the evil eye from the DM?