i thought the 7x57 was pretty much an equal to the 7-08 :? a 7x57 would be a custom option, whereas the 7-08 is available from TC.
you could always pick up a set of used 7-08 dies, if that was your choice. but....i reckon the 7x57 would have a "cool factor", and you already have dies.
good luck with your decision.
having both a .308 and one of those 7mm's wouldn't be bad. you could use the .308 for heavier bullets like the 165gr nosler, and use 100-140-gr in the 7mm. surely we can come up with a reason for owning both. :lol: