No problem... for 1/8" of twist, your covering should be able to hold it straight easily.

When you cover, be sure that the covering starts out snug in the diagonal from low corner to low corner on the upper side and raised corner to raised corner on the under -- before shrinking. (Best covering jobs have the covering pretty evenly snug all over, but most people get by without ever accomplishing that.) As you tighten up your covering, hold opposite twist in the wing, a little past what it takes to neutralize the unwanted twist... hold it that way till the covering cools a minute and your wing should be straight.

For an interesting insight on how much you can straighten )or twist) a wing with the covering, check the instructions for a PT-40. (I think you can find them at the Great Planes site.) Its wing is supposed to have 3/4" of washout and it was originally built with none and twisted entirely by the covering. The newer versions are supposed to be built with the twist already glued in, but They've cut the parts so precisely that even if you build in the twist they recommend, almost all of it pops out when you take a wing panel off the building board... so you're still stuck twisting in most of its huge wash-out with the covering!