Hi Steve,
My car spends most of its time on Quick Jacks. I have it positioned a little further inward and rearward.
Your setup is probably more stable with the jacks further apart to create a stronger base, less top heavy. I only use 1 set of spacers on the QJ, seems things can get a little wobbly if you use 2 sets.
It's a bit scary the first few times you are under it but as long as you are doing a precheck to make sure the car doesn't move you should be good.
Definitely agree with the safety jacks and something under tires.