Each of the other build threads that I have read had unique problems with the quarter panels fitting. The problems you are experiencing might be different from other people.
Don't get in a hurry to weld the quarter panels. Once they are welded, then trying to fix them gets very difficult.
1. Does the outer wheel house lip fit inside the quarter panel tightly? yes
I fit the qtr with the wheel housing floating and the clamped it, removed qtr and burned it it
2. The quarter panel should wrap around the tail panel tightly. No gaps. yes
but its to wide and trunk lid has 1/2" gap on both sides. it is not welded yet
3. Does the body lines on the tail panel line up with the quarter panel? Yes
4. Does the trunk drop off fit like it should next to the quarter panel? Im not sure I know what you mean
trunk lid and qtr end in the same spot and a ruler on the trunk would lay flat from sail to trunk edge across trunk lid and qtr.
5. Test fit the doors to see if the gap between the quarter panel and rocker is correct. This part was a pia
driver door is pushed as far bac as it wil go and about a 3/8" gap vertically and 3/32 along rocker and level with qtr window, Rocker ends flush at qtr and 1/4" short at the front and rocker is 1/4" shorter than the other car that I have unmolested. pass side pushed as far fwd and 1/4" gap vertically rocker is 3/32 at the front and 1/4" at the rear. rocker ends flush at qtr and front door edge
6. Other people have reported the sail panel does not fit the roof correctly.eh
Driver side qtr window rail was about where oe was, pass side was 1/4" lower.
7. Some people mentioned the gap where the quarter window goes is too wide.got a measurement?
8. My door jamb vents and rubber weather stripping did not fit. needed work
So far the driver qtr window chanel was stamped to far inboard. I cut off excess from outter and welded it to inboard. .IDK bout the vent fit yet.
9. Weld the trunk gutters pieces that are under the quarter panels. These strips of metal hold the trunk weather stripping.
10. If there are other jobs that are in the center of the car, finish them now. It is easier to get to them with the quarter panels off. I think im done in there
11. How are the gaps around the deck lid?****
Sides are half inch but I havent replaced tail panel nor burned that part in yet. I might section just the lower tail panel because its rusted down low.
12. Other people have reported the passenger side rocker was too long. I do not remember a report of the driver side being too long. Make sure nothing has moved after the car was cut apart. Make diagonal measurements to see if everything is square. If you push the rocker forward to fit the quarter panel, then the fender gap to the door will be too wide.not mine
The rocker on the passenger side measured exactly the same as a factory one the driver side was 1/4" short. I figured it would be easier to fix at the front than the back so I burned it in and will cut the front and section in a piece
You car is looking good! Keep up the good work.