Sorry for the delay in answering your question, I had not checked-in in a while.
I basically use the top of the posts(stiles) as the reference point for all vertical dimensions.
Once I am sure the stretchers(rails) are flush w the top of posts I then measure to the top of the lower stretches to ascertain they are parallel.
Ps I use the top of stretches as my reference edge as a matter of habit well.
In the case of the door frame, there is an additional frame and I have pre-cut the verticals to guarantee that the distance between the stretches will be the same when I proceed to glue-up.
Thank you so much.
No this was all done by hand, saws, chisels and hand planes.
And yes the shop is really very nice, I got tired of the small shed in the backyard
It’s about twelve by thirty feet with windows on two sides, fifth floor in a loft building, twelve foot ceilings.