Yeah,, there's an art to it. Lots of things come into play, including alloy. I had the devil's own time setting checks on one set of bullets when the alloy had too much linotype. Next time I added some wheelweight and the checks snapped on just like they were designed to do.
I seat my checks by using the Lee push-through sizer. I tumble the bullets in LLA. When they're dry I stick a check on the base, run them through the sizer, which crimps the check in place, then lube them again. I can push them to about 1800 fps with no problem at all.
Good luck with your bullets. They should be very satisfying whitetail medicine.