1 quart of oil too much will not normally come out of the rear seal. In the first place the seal is made to expand against pressure rather than let it leak by. If you are blowing oil out of the engine the problem isn't too much oil. Blowby is caused by compression getting past the piston rings. If the rear main seal is leaking it's because the seal is bad or there is a groove worn into the cranks shaft allowing oil to seep by.