The rear of the wishbone is connected to the subframe, if you are removing the rear subframe - you
cannot support the weight of the car on it.
Saying that, I would never use a wishbone as a support point anyway. I've got a few jacks and lots of axel stands, so depending on what you are doing, you can just support the weight on a jack and put an axel stand under the sill *just in case*. It depends on how much time you are going to spend under the car and what access you need.
When I removed the front wishbone, I found the best bet is to pop a couple of stands under the chassis leg mid-point, use blocks of wood to spread the weight.


Or support it at the chassis leg front:
