Originally Posted by
LeicaLad
BUT, on my Super Corsa, I picked up a used one needing the P-clamps. The problem is that the rack seems to want another foot of space out back. Those rack brackets are shoved all the way forward, and can't go any further. Is the rack simply the wrong size?

You could drill extra mounting holes further forward along in those mounting brackets to let the rack move further forward and sit level.
You will also have to slide the P-clamps down a bit on the seatstays to match the "shorter" brackets.