All good advice, but since 50% of my income comes from lighting bands comes and doing it with little to no set-up time, here's what I would do:
First, find out what lighting software you can rent. I say that because you can download it for free, set up and program the rig from now until show day. Most of them have a
visualizer so you can create your color and
gobo palettes before you ever connect a light. Then the day of, all you need to do is touch up the focus points.
Make a bunch of generic looks and don't try to do anything that is cued to a specific song or moment. That takes too much time.
As for what lights to rent,
call a few places and ask what they can get you within your budget. Some flexibility in your scheduling will help. If you're doing a Friday show, and can
return first thing Saturday morning, you'll have some leverage to get a better deal. A weeknight might even get you more of a deal. Also, what you have in
house will make a difference.
Par cans are great, simply because they're fairly cheap to rent. In Chicago I can get 24 cans on bars, a
dimmer rack and all the multipin cable for about $300. Your mileage will vary. Most places will
gel them for you if you give them a specific
plot, or tell them the type of music you're doing. Movers require less electricity but you'll get less beams.
As far as rigging, the towers are a fine idea. If you have the time and the labor. I usually like a 3 person team to
build a tower and hang lights from it, but it can be done with 2.