I got my Nickel over Steel rivets in and installed today - job done. They could be a hair shorter but I got them snugged down.
Hanson Rivet & Supply Co. - Cost Zero as the fellow just sent me "Samples" of 10 (they only sell in 100 or greater). I also got C4's (Truss) but as he said I wouldn't like them as the head was to wide.
C1-6-ST STEEL RIVET NICKEL PLATED
The little Tonka custom rivet tool I got off eBay worked like a charm too. Anyone that does this too, happy to loan it out. I even went ahead and bought set of screws that let me change the rivet tool heads out.