I used some leftover COB LED strip pieces to put my light bars together, and despite having 3M on the sticker I seriously doubt it's actually 3M adhesive - a few hours after I installed them two corners came loose.
I took the model for the diffuser retainer and put a loop in it to press the LEDs back in to place. At it's apex, there is 1.6mm space between the bottom of the channel and the point of the loop. Printed using two walls and arachne so the loops themselves are very thin and a bit bendy.
Since I had TPU in the printer already I just made them in TPU. They seem a bit too flexible to really stay in place, but I don't expect they have to do too much work so it should be ok. When I get some transparent PETG I'll probably reprint them with that, just for the rigidity (my entire riser is PETG, so I won't be using it at all when printing ASA or other high-temp materials).
The author remixed this model.