re pole piece size..... if you can get some callipers and measure the polepieces diameter (i think its probably 10mm), then get a drill bit of the same size and warm the top of the shank up with a flame (about 10 seconds should do it) then carefully stick it through the holes from the top. pish the drill but through sufficiently and use trhe cold part of the drill bit to cool the plastic.
if this is done right, it will result in a very clean looking accurate hole that should have a very close fit to th pole pieces.
ive put a couple of the 1st batch in the package for you to practice on if necessary