I used to run a sand volleyball league & tournament center.
We had 8 courts running, but built the courts gradually (started with 2, then expanded).
We learned (the hard way) how to keep our courts "dry".
Now, I will tell you there is NO way to keep the sand dry short of covering the courts with tarps (slightly elevated) whenever you're not playing.
But, there is a way to build the court so it drains quicker and thus dries quicker when it does rain.
1st...Mark your court area with at least 10' extra sand area then the actual court dimensions.
2nd..you have to dig down almost 2' below grade. Then, get some gravel/stone (3/4 down works best) and put about 6" of this into your pit. You can put more stone in, but then you risk someone finding stones while playing.
3rd...put your sand in. Double-washed masonry sand is the ABSOLUTE best sand you can get. It's "powdery" when dry, and doesn't get too hard when wet. It can get dusty in hot-dry weather, but you can alleviate that with a quick hose-off. It's also easy to rake wet or dry and has no shells.
4th...No matter what you do, you'll have to rake the sand just from playing on it. If you rake it level after playing a session, you'll find it a much better surface the next time you play.
Hope this helps.
PS...if you're going to put lights in...you should consider high-pressure sodium lights. They take awhile to light up...but light the court without blinding players looking up.