Both plants were looking good two days after transplanting, so I decided to FIM on day 25. They seemed to respond well and didn't show signs of stress that I could tell. The plant is definitely getting bushier and some of the lower axillary branches are starting to catch up to the old top of the plant.
I watched a video where a guy had 4 plants of different heights. He raised the pots of the 3 smaller plants, each by different amount, to create a level canopy. That might help you if your 4th plant is smaller.
good luck with it all, I'm a noob so cannot offer more than 3rd hand advice and best wishes.