For the record, I only use the stock scissor jack on the fiberglass and I use a floor jack on the frame or the tranny. That's not for any structural reason but for a practical reason.
I jack up the car with the scissor jack enough to get my floor jack under the junction of the 'T' and the backbone. Then I jack the front of the car up onto stands. Then I jack on the tranny so that I can put a "stand" under the rear tranny hoop. I built one out of 2x6s. It looks like a small stool but anything that will support the rear of the car on the hoop would be fine. I reverse the process when I put it on the ground. I lower the rear onto the ground, lower the front with a floor jack till it's high enough to use the scissor jack, then pull the floor jack out and lower the scissor jack.
One day I'll design something to accelerate the process but I don't have a lot of room in front of the car so it will be a challenge!
