bman--The keys to successfull drawbore and raising will come from your understanding and execution of building with control. Never assume the foundation is level, square or on dimension, verify everything, chart varience, setup a numerical scribe for post lengths and layout the footprint to your best. Your goal is to have plates, ridge and bents as level, square and straight as possible. Within the bounds of the greater building, the details of joinery and components, loads are supported and forces are resolved. So while you are thinking ahead, ask yourself, how will I know what I need to know to get predictable results? The question can be asked continually and the answer is in geometric planes, lines, points and solids, and their relationships of dimension, square, parallel and slope. So in a sense, layout of a drawbore is no more difficult than any other detail, once you get it. The trick mostly is the control of boring perpendicular to reference face, use of a boring jig, antique boring machine or a drill frame are the usual means.
My suggestion to you, if you feel cautious, is to bore through the mortise and prick the tenon during fit up with a peg modified into a ecentric center punch ie drill the end of the peg off center,press in a short piece of nail and file a point.
Remember the draw peg should be considered a spring and requires taper in the active part of the bore.
I while erecting set connecting girts, plates and braces to secure the building as I go. I bolt and strap strongbacks and never clamp.
I have found that a survey of the foundation is my best guarantee of an accurate frame.
