The cost of the final product is what stops me from using them. I sent an email to a led sign maker awhile back, and it seems they've blown me off. No answer. Hmmmmm.
I mentioned growing plants under them, thinking that they would suggest the most favorable lights, but perhaps they read "pot grower" into my request and just blew me off.
I'll check with another and not mention plants this time. I'm going to tell them the ratio of white/colors I want with the brightest possible leds and the size of the "sign", and see what kind of price they come back with.
I'm going to go with a 3 x 5 foot sign for pricing.