getting back to reefing need advice 24g jbj nano setup

The wife is finally caving ina nd letting me set up a tank after 5 years out
of the picture. Can't do a big tank yet so I compromised to a 24gal JBJ
NANOCube. I am looking for some info about how much sand, rock etc people
are putting in there. I am trying to figure out the budget so I can get
real nice rock, perhaps a few frags, and stuff.

I am planning on housing a pair of tank raised perculas, and a few hermits,
plus a cleaner shrimp or 2 or maybe a perppermint shrimp or two. For the
coral, I will stick to the basic beginner stuff, shrooms, zooanthids, colts,
leathers, xenia, etc.

Also, any info on slight mods people have done (this will be in plain view
so it needs to be neat!) I've read that many folks take stuff out of the
back compartment and drop a bunch of LR rubble in there, then add a small
light and make an inline refugium. Yet I cannot find anything that says how
they add the light.

Just anxious. Thanks!