this is two over a 55, if that helps you picture it (48" tank) kinda dim in here right now but you get the idea
as you can see, i did not hang them with a great deal of care

they come with the carabiner and everything below. so i put a hook in the ceiling and hung them with that invisible picture wire they sell.
also, the fans are a little loud for me, but i don't have anything to compare it too, maybe theyre all like that. i guess thats why people use canopies.
the full spectrum is cool, it looks really natural except for a couple weird crevices where the rock makes like a spotlight for only one color. so my chalk bass has a purple disco cave to hide in

ive seen them recommended for 40's a lot, i think its fine. it penetrates my 24" depth no problem. if the corners are too dim, the nem will just go someplace brighter, you can put some mushrooms there instead.
they took a couple weeks to arrive from ebaychina, idk if there's a temporary solution for your nem