I have a set of Lee dies for my .454, but I haven't been loading long for the the .454, so don't consier me an expert. I bought the three-die set used for $10, so I wasn't out much if they were crappy, but they haven't been, if they are stamped .45 LC/.454 C, make sure you back the seater die wwaaayyy out because the instructions are set-up to seat for the .45 LC, and you'll crush your cases if you set them up this way, trust me, I can give you pics if you want them. After I had them set up correctly, they work great. I did try crimping some cast bullets with the seat die, but it's a PITA because you hav to readjust the die between seating and crimping, which makes my ammo inconsistent. It didn't crimp real well, so I went out and dropped $12 on the factory crimp die for the .454 Casull, night and day difference, you can crmp as heavy as you want to and the cases won't buckle, again, I have pics I can show you. The factory crimp die actually will creat it's own crimp groove if you don't want to use the one provided, and on heavy bullets I make my own because the throat on my Encore barrel is so lllllooooonnnngggg, I can't even reach it with a 370 gr. GC resting in the case!
Hope this helps.
Selmer