I print the letters face down on the print bed with a first Gcode (make sure the geocode doesn’t stop the motors at the end). Then you print a second file over it for the plate that has a gap of your initial layer height where the letters are. The benefit is that if I fail a print, I only wasted on layer not a whole print.
tl;dw: use a large gauge copper wire to align next to the pins, add some solder so it contacts all the pins at the same time then heat up with your iron. You can use two soldering irons if double row devices like arduino pro micro 😉