As for getting all four off the ground metester,
Ive done it with my mate in the vp you see in the pic, had a nice thick slab of concrete in the garage though, pretty much level.
It can go bad heh, as someone above mentioned , while jacking up the oppisite end the other end on the jack stands is prone to shifting,
I learnt the hard way, me mate was jacking up the front after the rear was placed on custom made 100mm x 100mm jack stands I made at work, we chose the thick hooks at the rear to sit them on....
Well the car somehow almost came off one of the 100mm wide x 100mm wide stands, somehow started sliding off it with its 10mm wide hook it only had another 6mm to go to fall off. after being placed in the center (it travelled 40mm while jackin the front end up, and i had to say WOAH WOAH WOAH, and "Check this sh*t out!!"
And he stopped jackin it up and came around the back and was like, "man thats close."
I think its all because we were jacking from all four sides and not directly in the middle of the car , but as i said be careful.
doing it all again, i'd have the handbrake on full, transmission in first gear on manual, or Park on auto.
Jack the front up support on stands either side on the chassis rails, then jack the rear up at the diff slowly and dead centered and place the stands on the hooks myself, cant see any other spot to place them that can take a lot of load but i havent had a commodore very long and dont go under it at all. Take care, and remember to use back up measures like spare wheels on a few blocks of wood or something.
MY old man has been saved by a few spare tyres stacked on top of each other in the past, gave him 1 inch of head room to squeeze out or something but still saved his life. So yeah try that method, two spares stacked on each other , then slid under for a fail safe measure.
I like your car ramps for the front idea, its alot quicker and safer