The goals were:
Get 40-50 mms of PAR, for sure, with good probability of being able to get twice that.
Hanging no more than 20 inches above the top of the tank.
Good coverage of the whole tank.
Some shimmer effect, if possible.
No fans, if possible.
I believe I can meet all of those requirements, and have the ability to do some limited adjustment of the color temperature too.
The parts cost? So far it is:
I have my fingers crossed as to whether I will make a profit on this.