I don't see why that wouldn't work. That is basically they way I lubed the ones that came with the Whiteline bars I put on. The only thing that might happen is it there is a little rearward force pulling the bar back, from the control arm bushings being tweaked just a little. Then the bar could pull back and you would have a hard time pulling it forward to get the bolts back into the bushing brackets.
I would do one at a time and tie the bar to the tow hook on the front of the vehicle to keep it from moving. Use something the won't stretch like chain. Just a thought.
I would do one at a time and tie the bar to the tow hook on the front of the vehicle to keep it from moving. Use something the won't stretch like chain. Just a thought.