I do it all by feel (WYSIWYG). After some time and practice I just knew where the plans had to go. I used to stand back and look for the intersecting lines (at one point I was using a protractor), but that is now long past. Now my decsions are made under the dark cloth with loupe in hand. Now I have asemetrical movements I find it even easier than before.

My advice is to learn the rules (schemplug & hinge), use them until you understand how they work. And you will soon make the jump to just knowing where to put it all.

I never really understood the hinge rule (trying to understand the book) until I saw these animations. These helped with my understanding. Much easier than the tables he presents. This is the link to the article that have the animations in it.

http://www.trenholm.org/hmmerk/VuCamTxt.pdf