Why are you talking about being a couple teeth off with the belt, in the same question about using a timing light??

I hope you got the camshaft timing OK, when assembling the engine. That's the markings on the camshaft sprocket, with the crank at TDC. That has nothing to do with a timing light.

Now the spark timing is checked with a timing light & adjusted by twisting the distributor. Don't mess with teeth of the timing belt at all, at this point.