Whoa! Before you start re-dishing a wheel, you have to measure the dish to be sure its off.
To measure the dish, pull the wheel all the way back into the dropouts and measure the distance from the rim to the non-drive side chainstay. Now take the wheel out, flip it over and do the same thing. If the distance is about the same its NOT a dish problem.
I would just center the rim between the chainstays, theres always a little play in the dropouts, and just ride.
Il faut de l'audace, encore de l'audace, toujours de l'audace
1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1