Watched a video by a pro builder pressing grommets into a headstock using a purpose built press. I was fiddling with a few things to see if I could replicate something similar with stuff I had in my shed when I noticed my many Phillips head screwdrivers seem built for the job. Slip the grommet on the screwdriver. Push it in and a couple of taps with the hammer and Robbert is your avuncular relation!
Nice! I just use one of those squeezable hand clamps myself. Seems to do the job. Your idea will ensure it'll go in straight!