Bob,
If your normal L.O.P. on a SxS is 14 3/4", you may find your comfort level with an O/U is the same or even a tad longer at 14 7/8" or even 15". Also, previous suggestion to bend the stock before making big cuts is a good one as L.O.P. will affect cast at face too. If that stock has cast-off PLUS twist out at toe, then you've got another issue to deal with, but assuming its pretty neutral you may never notice.

"I hate rude behavior in a man. I won't tolerate it" - Capt. Woodrow Call