Yes, ask for a fitted punch when you order and include the $10 fee. This is the best way, as I make it to fit the actual diameter of the mold I make for you, and you'll have it when the mold arrives, rather than having to mail off another order.
I can make you a 250 gr bullet mold, with pb or gc. FA revolver have very tight chambers and cylinder throats, all of them. You pay for that precision and they deliver, but barrels are always oversize, so lapping the bore will do nothing if the cylinder throats are not opened up, which also demands opening the chambers! I've only known of one man who did it in my 30 years of mold making, and he obtained stunning accuracy for his efforts. But these guns shoot very well in stock condition. Order a 452 bullet diameter, which probably won't need sizing smaller that that with the light weight, which cannot have a long nose length tha would put the first drive band out into the throats. In other words, try sizing 452 and if they chamber without resistence, shoot them that size, but if they stick in the throats, size to .451.
FA intentionally makes their barrels oversize to reduce pressures with jacketed bullets, as the 454 is intended to run at very high pressure. For cast, just work up a load that shoots and when you see accuracy tighten you'll be at the 'sweet spot', where the bullet bearing expands from the back end forwards for about half the bearing length.