Where to get fuel sending float for my '66?

[Rust-O-Matic]

I replaced the fuel sending unit/pickup tube in my 66 a year or two ago, and just now got the rest of the truck back together and almost roadworthy. Realized my gas gauge wasn't working so I pulled the (basically) new sending unit to find the float is missing off the end of the float arm rod. I presume it's floating around in there, but I have no desire to try to pull the tank again or try to rescue it.

I'm having trouble finding a replacement float online. Does anybody know where to get just the float, or have a part number and/or dimensions? I found a few on ebay listed for Fords, which appear to have similar dimensions to the hook on my float arm, but I don't wanna get one that doesn't fit right or won't fit back in the tank when I reinstall the sending unit.