Is hand thicknessing a problem? Ida thought flattening the face of a twisty board is the hard part but after that taking off the back down to gauge lines is relatively easy.
Accuracy: IMHO accuracy itself less important than the appearance of accuracy, which isn't quite the same thing.
That's where woodwork is so different from engineering. There's a range of woodworky tricks to make things look right such as undercutting, offsetting to make shadow lines, mouldings to conceal joins etc. The main trick being the final fitting of pieces together by easing in with a block plane, or dropping a tenon saw down a gap etc.
Thats why a sliding bevel and a school protractor are good enough. The precision of engineering measuring devices is somewhat wasted as one can't in any case saw, or chisel precisely to the line accurate to .01 mm. You are back to hand and eye skills, like it or not.
cheers
Jacob