Wow,
I haven't seen the(I beleive it was actually called Dexron II "H") spec in years as it was only out on the market for a short time before DEXRON III/Mercon hit the shelves.
I believe the order of DEX ATF's were, (and I could be wrong on some of these):
Dexron
Dexron II
Dexron II "D" ???(Never seen this one, only heard it existed!)
Dexron II "E"
Dexron II "H"
Dexron III(IDK if it was always called DexIII/Merc)
Dexron III/Mercon
Dexron IV(I've never seen DexIV, only heard it existed!)
Dexron V ?(I think the "V" was skipped over?)
Dexron VI(current Dex ATF)
But anyyyywaaayyy! I think you'll be just fine.
My sisters '98 Camry V6 auto tranny also only held ~ 2.5 qts on a drain/refill so, we did it about every year. Sold in '11 and everything was running fine using Wal*Mart SuperTech DexIII/Merc since '01.