I have a ull set of sizer from UK Neil (4.48 to 4.53). Sized a 100 through each straight from a tin of 4.52 JSB's. With luck this weekend I can do some experimentation and see what suits my rifle.
Did find that 4.52's did not fall through a 4.53 sizer.
Intetntion is to then weigh bsome over the next few nights to get a quantity between 8.35 and 8.55 grains and then size them and compare the groups sizes at 50yds. Could go through a lot of air this weekend.