Before I even ask the correct answer is just buy the right stuff and be done with it.
The situation is that my Dad has aquired a 264 WM. Now I don't want to spend buckets of money for 3 boxes of jacketed since I've already laid out for dies and made brass. Can I get buy to just shoot it to see if he wants to keep it sizing a27-130 FP to (arbitrarily) 268 or should I just eat it and buy a 260-120 and patch it up knowing that there WILL be at least 1 25cal in the future.
I guess what bugs me most is that I can get a couple of sizers and use what is on hand or buy a mould and a sizer for just a little more than those 3 boxes of jacketed.
So if it were your shoes which socks would you put on?