It's more prone no slide when you have an angle, like it is from the sides.
If you don't have anything else, a folded rag/piece of carboard on the jack cup will improve a bunch...

 

its not the best...see the jack in the second picture is the aluminum racing jack i was talking about. It has a much bigger pad and has the rubber. It is also lower profile and will get into tighter places. I would put something in between like a piece of wood perhaps.

 

Thanks guys. I'll just use a piece of wood, jack it up by the cross member like in the pictures, and put the jack stands in the pinch welds toward the front of the rocker panels.

I've been told it's a good idea to leave the floor jack in place with just a little bit of tension on there as a safety thing once you lower the car onto the floor jacks.

 

eh, i never do, i have had my car on 4 jacks for 2 days before and no issues, it gets in the way sometimes, you just have to be careful and not kick the damn stand out!

 

Yes and no.
If you have heavy duty stands, you don't need the help of the jack, period.
If you have sh#ty stands, then you need to throw them away, lol.

 

It may seem frivolous, but it couldn't hurt for it to be there.

 

Couldn't hurt at all.

Your jack seals life span will be reduced a lot more though.
And rebuilding a jack costs as much as a new one...

 

I keep the jack there along with the stands as extra support/safety. Might as well.

 

Or, you could do this. No jacking involved.

 

Make sure you stop at the fourth step there ZZ
Cool ramps though, and cool car too...