Can subframe connectors be installed on a rotisserie during a resto?


Someone told me that subframe connectors need to be installed with the car fully assembled and sitting on all 4 wheels.

How critical is that?

I have a car on a rotisserie right now.
I don't really want to reassemble the car just to install subframe connectors.
I also don't really want to weld on fresh paint as soon as the resto is done.

Any tips or suggestions?