Peg hole from shoulder spacing

[treemuel]

I've worked on two timber frames so far and both used 1 1/2" tenons with 3/4" pegs laid out 1 1/2" off the shoulder. I'm getting ready to build a frame using 2" tenons with 1" pegs; is it typical to lay out the peg holes 2" off the shoulder or perhaps only for joints in tension? In this case there won't actually be any joints in tension (other than possible racking or wind loading), since it's a shed roof design. I was thinking that at least for the girts and braces I should stick with 1 1/2" off the shoulder, since the short tenons (3") would otherwise leave very little relish. 

Thanks for any input!

[Jim_Rogers]

1 1/2" off the shoulder is standard with 2" tenons and 1" pegs same as 3/4" pegs and 1 1/2" tenons. the reason why is the distance from the peg hole in the tenon to the end of the tenon.

Jim Rogers