I'm considering this too and surely would like to see some finished pictures! How did you resolve your installation questions?
So this project took a couple calls to the manufacturer, a lot of unproductive internet search time, and trial/error....but now that I'm done hopefully I can offer some suggestions.
I did 75 lights (3 LED drivers, 25' fiberoptic lines) on a sunshelf. Usually these are placed on the deeper parts of the pool floor, and kits can come with much longer lines. The lines were pretty durable considering all the tugging and stepping on: jacketed and 2 fibers/light strand. The star consists of a base plate with the 2 fibers feeding into a vertical acrylic rod (partially hollow at bottom for fibers). The LED drivers live in a circular container meant for partial burial.
Per the instructions, these lines were placed after gunite.
Acid wash was prior to installing the lines. Portland cement was applied to protect the fibers and star hub (instructions). Marcite was done after, requiring hand troweling and repairing several lights in the process. Overall, its suprising more didn't break considering it was like a landmine zone. The shelf is 6' x 19'. 75 lights was way overkill, but I placed the 3 light zones evenly allocated to allow for future tweaking.
Trimming took a couple experiments. The vertical riser is acrylic, and it charred with a hot knife or tile cutter. Best tool was my ridgid multi with a diamond blade, and final cut was with a dremel. Trimming needed to occur after plaster dried, because the vibration disturbed the finish. This didn't really delay filling, as they were only on the upper shelf. Might be an issue if on the bottom.
Problems encountered: Even though I did 3 rounds of chipping away loose portland cement and cleaning up, the floor feels somewhat wavy (hand trowel) and actually a little hollow sounding in areas. Again, I think these are usually placed on the pool floor not where walking normally occurs. I expected a thicker marcite, but they know what they're doing.
Hindsight I would have stuck these in the concrete during the end of the shell creation. The dowels always broke at the insertion base...and covering these with cement would have definitely avoided them snapping so easily. Alternatively, grinding out a spot for the lines and bases would've worked. Either of these would have avoided the uneven floor.
The other issue was the mess of fiberoptic lines when the slack was pulled out of the shell. I ended up burying them in a plastic container, sealed but perforated bottom. Its possible to hotknife these fibers, but at that point I was over it.
Overall, we like the lights...they're a neat feature. If I did it over again, I'd have done less lights or spread them out more into the pool. If anyone has any questions, feel free to ask.
