I have a few "C" clamps, but these are the only two I use... but only because I'm too lazy to swap them out. If I ever need to move that tray, they'll be relegated to the archives. These may be ok on metal, however, I reckon if you want them to hold, they'd scar the bjesus out of wood
If your first cut is too short... Take the second cut from the longer end... LBD