Kyode,
I would go with the 300 WM and not look back (A 17 inch 300WM will be on the coat-tails of my Patriot & that elk won't be able to tell the difference!). It is also a great LR vartridge. Choose your smith wisely and don't over work your brass and it should be no problems. You already have a headspace indicator so you shouldn't have any problems. Consult with the guys who are currently using them in Encores and visting with Mike Bellm or Mike Sirios wouldn't hurt either if you run into problems.
Ernie