Hey I dug up some random pics of tying plants down and bracing the stem.
I do this through week 2 and bend and supercrop branches til I end up needing to support the buds toward the end.
Then you just stake and tie the plants as the lower branches (if you leave them next time) stretch up to become tops.
I grow a perpetual garden with all stages together and all different strains and crosses but the last pic should give you an idea of managing the space.
It is easier and more productive for yield to grow plants together like in the op. With some planning and practice you can have a sea of tops in there.
Oops. I forgot to black out the border on one of the screenshots.
I know it would be heartbreaking but if you have to remove a plant to make it all work you would get better results and likely have less problems.
Goal is to keep the canopy in the sweet spot where the plants look happy and vigorous.
I would guess at least a couple of feet or more from that hot bulb and you need good extraction. And a fan or two pointing between the lamp and canopy helps.
You have to experiment for best results with air flow.
Good luck.