Thanks timmur
The plusnuts look good - like you said before ... same principle as a rivet, but looks stronger. Looking at your project planning ... I'm pretty sure that you've checked the loads on the nuts and also the steel in the ceiling panel.
I'm a liitle confused about the use of a screw or a bolt. It looks like the inside of the exposed part of the plusnuts has a thread, which you could screw a threaded bolt into. Does plusnut also sell a bolt or screw to fit into the nut or do they have recommendations - it would be great if they had tested a range and know which ones work best with their system?
In any case ... the above is just micro stuff ...the rivnuts will be a nice clean install. Really looking forward to seeing the lights hung - I like the look of the GBs and reckon you have designed a very functional and beautiful grow environment, that should put a smile on your dial everytime you enter it .... nice.
The plusnut takes an 8-32 screw and it can hold a lot.