I think this has been covered somewhere, but I can't find it exactly.

What was the out come at the cooler? Pro or con?

Acceptable offsets depends on the size of the peg and length of the tenon and the amount of common sense. Mostly an eyeballed 1/8". My reasons for drawing the joint is a time factor. It is done when the joint is done, no more tools needed at raising time. you are right there doing the work, the peg hole is the least of the work. It would be risky to bore the holes right on with the joints apart, the risk is miss alignment and forcing the joint apart so that is not a choice. So reason would say draw the joint and have it done. Than there is the shrinkage factor. Basically its just the way I have always done it. Tim