I have now done one driver quarter and deep tub on a 69 Camaro. Take your time!!! Currently I am doing the other quarter, tail pan, and so on. Not to hard to do. If you plan on doing a mini tub while you have the quarter removed I would recommend bracing the the inside of the car. This is cheap insurance to make sure the car doesn't move. I would use square tube or angle. I cross braced the door, put in a bar going from side to side. If your interested in seeing this let me know and I can take some photos. The last thing you will want is for the car to shift. My car did with the driver side quarter and tub removal. I then had to fix this problem. I was told to put in some braces and I didn't because a lot of what I found on the internet only showed a couple of jack stands. My bracing looks like **** but it is almost like a mini roll cage. Also test fit you panel. Depending on who stamped the panel it may end up being bad. Sometimes they end up being short in the back, front, etc. It will need to be tweaked a little. But you really should not have to weld on a one inch piece of metal to make it long enough. Actually have seen this done.

GOOD LUCK. TAKE YOUR TIME.