Your frame is not a good centering tool. The seatstays are not perfectly centered on the frame nor are the dropouts. You are lucky if you get within 3mm perfect alignment between the seat stays near the brake bridge and the dropouts. Every time you remove and replace the rear wheel to reverse it, you will have to adjust it exactly the same in order to assess the rim centering on the hub. Basically, you will just be chasing your tail and will never center it properly. I use a wheel centering (dishing) tool to check rim centering, and always do this first before I attempt to check and adjust lateral and radial runout. Then, there is the issue of properly tensioning and stressing the wheel to keep it from constantly getting out of true.