I size and apply gas check with a Lee push through sizer before PC so that wouldn't be a problem. One might also be able to size the brass used to punch the holes out a bit with a Lee neck flaring die. Or if one already has the Lee flaring die body a $6.50 neck sizing button from NOE that fits that body would give you a precise neck size of the brass that you use to punch the holes. Might even try some 1/4 (.25) tubing to see how hole from that would work. .That .027 difference in size might still be snug enough to prevent falling.
Has anyone tried tumbling bullets and PC in a FART? I'm sure an empty powder bottle would fit. Tumble seems like it might be more even than my vibratory brass polisher.
However you do your bake I do think you need a way to confirm the temperature inside is correct, thrift store toaster oven dial temp and inside temp are related but not that closely. I would say knob is about 40* off of actual on mine.
If I had a bigger oven and wanted to spend the extra money a PID might be very useful for baking PC. For now I use a thermometer and go to temp, then run for a set period of time +/- based on bullet mass or ambient temp then hammer test the end product. Bullet mass is a heat sink, count of bullets being near equal the 255 grain .45 bullets are going to keep oven from reaching full temperature longer than same number of 158 grain .38's or 70 grain .223 The tool I use, spring loaded small needle nose pliers determines how close bullets can get so count of ones that stand up doesn't vary by enough to make up for the additional mass of lead to warm to temp. Only talking 1 or 2 minutes at most difference.
Has this been tried with cheap Walmart silicon baking sheets?