1st gen tci 4 link quater panel buckle woes...

Hi guys, long time reader first time poster here... I have a 63 ht that i am building usuing tci 4 link rear, frame connectors, front suspension and dse mini tubs. Before i started this project last fall i did my research, i have heard of issues when installing a 4 link or similar setup and not supporting the car correctly. I lifted the car by the rear axle, leveled everything and then supported the car by the rear shackle area, front "torque boxs" by the front spring mounts, and by the front subframe. THEN I lower the rear axle and removed it, this way the car is supported and weighted like it always had been with leaf springs. It stayed like that the entire time i worked on it, nothing moved, no signs of any issues. I did the dse tubs first. While the frame was open i added 10 steel to the inside of the rail in the tub area. I also added at 10 guage plate to the entire front portion of the frame. The only section I didnt reinforce is from the rear of the wheel well to the bumper/ shackle area. I bolted in the tci suspension, frame connectors, and fitted 295s and all looked good..... until i lifted the car by the rear axle and supported it by the rear axle as if it was sitting on the ground... then i noticed the dimples or small dents by the front of the wheel well, then i lightly touched the lower quarter panel farther forward and the whole thing popped in ..... made me sick..... If I lift it by the rear bumper area everything pops back out on its own.. question is,, what do i do now?? is this because i didn't reinforce the rear section of the rail from the tub back?? Did I do something wrong.. I called TCI and they said the mini tub weakens it and I may have to shrink the quarter panel?? Problem is the car is painted...

Should I support it by the rear and add plate the rear section of rail?? Add a rear roll cage or something?? Starting to feel like I ruined a good car and wish I would have kept leaf springs and be done with it.

Id post some pictures but I haven't figured out how to do that yet...
ok, pictures added in my profile...

Thanks, Al