I just finished putting my 30 coupe body back on the frame. It took four days of adjusting, adding and removing shims. Thank God for a helper. Sorry I don't have a digital camera so no pic's are avalable.
You most likley have heard that you should take pictures before dissassemble. Best advice anyone gave you, I didn't. So I didn't know if the body lines were perfect before, hence was I trying to make the body lines match now when they didn't before? All I had to go on was what shims were on the blocks I removed when I took off the body. Remember this car is 80+ years old. Gravity effects cars too!
You will hear about the frame sagging. That must be checked and corrected if too bad. The way I did it was to pull a string from the front to the back of the frame rail on each side. Look for low areas under the string. Mine had less than 1/8 of an inch. I did nothing to straightin the frame. Figured I could ad another shim.
The article from the barnyard site was helpfull in that the body shift like a box. If the rear of the doors are low, the front of cow needs to come down, If the rear of the doors are high, the front of the cow needs to go up.
I started at the front. Placed a 2x4 under the body at the very rear end of the car. The body is way to heavy to keep lifting up and down. This allowed me to wiggle the bolt through the body, blocks, shims, welt and into the frame hole. no nuts at this time. I started with one shim under each wooden body block. When all bolts were through the frame on both sides I removed the 2x4 and started the washers and nuts. Tighten ALL NUTS. Then crawl out from under the car and check you door alignment and reveals. Make sure you open and close all doors. And that they open and close smothly. Check the gap along the hinge side of the door. Adjustment can be make to open or close this gap also.
At this time the fun begins! Any adjustments you need to make is made by adding shims, but I had to loosen ALL nuts and raise the body to add any shims, and then retighten all nuts. I read somewhere that the adjustment you make by adding a shim of 1/8 inch thickness will raise the body 1/8 inch. I did not find that to be true.
Most of my adjustments was made at the cow. I needed to add three shims to the front of the cow to lower my doors, and one shim on the third wodden block to raise the body. Alignment is not perfect but well with in my accecptable tollarances. Doors open and close with ease and the gap along the door at the hinge is equal.
Good luck and DON"T get frustrated. I made adjustment that took the body the wrong way and had to remove them and start over.
It's like fine wine it takes time.
Sorry for the spelling, not my best subject. hope this is helpful, I spent many weeks looking for this type of info and didn't find it. So not wanting to hold back by project any longer I just jumped in.