Joel - my original clamp fits fine with a little extra room on the Red Top. Must have been a few batches later?
Sorry to hear about your battery troubles.
If you have the 50mm wide, very first thing I ever designed and manufactured clamp, it will not fit the Red Top. It's a perfect fit for the Panasonic, but may not fit many other batteries.
The 07-09 Universal clamps will fit the 07-09 Panasonic, Optima, and several other types of batteries.
The new universal will fit all FJ stock Toyota batteries (07-12 Panasonics), Optimas, and many other batteries. I have seen an Ellis Precision Universal clamp installed on a DieHard as well.
The biggest issue is the notch on the bottom of the clamp. The Panasonics we had in 06/07 were exactly 170mm wide, and the clamp has a 170mm notch. It seems most other batteries are 6 and 3/4 inches across the top, which translates to 171.45mm. Too big for the original Ellis Precision clamp. The new clamp designs are machined to 173mm, to provide a bit of clearance for any injection molding discrepancies.
Let me know what battery you go with. My FJ is getting harder and harder to start now as well (06 build).