I read somewhere that it is possible to use 458W dies to reload 458L. What adjustments does one have to make? How do you resize full-length?

I used standard 458 RCBS dies when I was loading for my Lott, never encountered any troubles. For resizing, you won't be able to screw the die down all the way, just back it up a few turns and try a case. Once you find the resized case works through the rifle with normal effort just lock the ring on the die and load as normal.

I've also used RCBS 458 win mag dies, and they worked fine. But, with Hornady producing true 458 lott dies, at reasonable costs, I'd go with the Hornady dies.