For moon light it is best not to be too bright in order to get that natural contrast we view under moonlight.
So led of maximum 1 watt per sq ft is more then enough.
The use of blue led is closer to moonlight then white led.
If you able to get hold of a lunar track to control your moonlight it is even better.
You can use a 2 to 3 mm aluminium bar or channel to hold your moonlight as the heat dissipate is small.
Cheers and Happy DIYing