Where to buy electrical connectors

You could use a hex nut. I wouldn't. Tightening the nut or putting any force on the senders contact post could cause a fuel leak. This already happened to another member a few years ago.
I can send you a #10 connector that will fit your fuel sender if you want.

I was not aware that was possible, but then again I didnt think about it either. That would be awesome if you could help me out. Heck even if you have a pick of it and its a common connector that I can get locally I could go that route. I'll send you a PM.