I would ditch the dual 1604 approach. If you want a physical board, look at the soundcraft si, behringer x32, A&H qu, etc. You get all your fx, comps, gates, graphic eq's on outputs, DCA's, at least 8 monitor mixes etc. Even more budget, and actually what I use most of the time because it's so easy, is the xr18. 16 preamps, 6 separate monitor mixes, all the rest of the stuff I mentioned as well. I have gotten really used to mixing on a tablet, and actually prefer it now as I can mix from any position in the room. I still bring my old trusty 1604vlz as a backup, but have not needed it.
In the capacity rooms you are doing, powered speakers will really help you out as well. Most are optimized to be as efficient as possible, so that most of the time a single 20amp breaker will get you what you need. In the capacity target market you are talking about, getting the club owner to strike the panel for your distro box or having actual dedicated dual or triple 20amp just for stage is rare. Most of the time I'm lucky to get 20amps without the bar signs plugged into them. In my rack of my xr18, I have a rack amp meter/power strip to check my draw. The weight and footprint is important as well. Most budgets in this target are not enough for you to afford more than yourself and actually make money, at least with bands. Corporate stuff/weddings etc pay more, but live music stuff is pretty lean depending on your location. I have designed my setup for 1 man unload, setup, run, teardown, an load back up as fast and efficiently as possible. I have all LED lights as to not draw too much current. I keep them all pre-wired and in cases so I just set up my trees and have 2 plugs to plug in, done.
Do a lot of research, especially watching youtube videos. Look at other setups, both good and bad, to determine what will serve your market best. Go out and watch your competitors to see how you could do a better job at a cheaper price. Always sell yourself on and provide quality first though. A cheap horrible sound company will not be around long.
For power, I run multi-outlet drop cords. One cord circles the stage and allows all my powered speakers and monitors, as well as on stage musical gear to plug in. You keep the stage cleaner and it is faster to set up. As I can run everything on a 20amp breaker, my multi outlet drop is 10 guage, which is more than enough for the load.
What I run:
Boards: xr18 (outboard router), or soundrcraft si expression 2
Main Speakers:2@qsc kw181, 2@qsc kw153, 2@yorkville ls700p
Monitors: Up to 6 qsc k12
lights: 8 led wash lights, 2 LED jelly gressors for the dance floor, 2 small LED disco ball effect lights for ceiling/walls above and behind stage,
Cases: SKB gigrig (6u front, 12u top) for all my xr18, 1604vlz backup board, power cond/regulator, laptop on sliding shelf, 4umic drawer in back, dual band router.
I have the 6u gigrig "extender" that to top skb sits on. The bottom extender gets the gear/board up to a comfortable height, has locking casters, and is 6u tall and pretty deep to store ALL cords/cables I need including power/subsnakes. I use a 48" long, 24" wide, 8" deep semi soft keyboard case that hauls my pre-wired light bars.
I can have all my equipment offloaded, set up ready to soundcheck with all mics and everything in about 40 mins by myself. That is with 6 to 7 piece bands.
Keep everything as simple and lightweight as you can. The less moving parts you have, the less chance for issues. No need for driveracks or processing as the new digital stuff is more than adequate for live sound at this level. Have a good selection of mics. I carry about 30 mics in different flavors. Have extra xlr cords, and while most I have are 25 to 30', I carry 10 that are 10 to 15'. I set up my gigrig usually at side of stage as I mix almost everything on tablet, but I always have a hardwired laptop to the router incase wifi goes down and also because I multitrack every show as I can maybe increase my revenue that way with minimal extra work.
The really nice thing is this ALL fits in my pickup bed securely, and my drumset goes in the backseat. I don't have to bring my trailers and try to find parking in a downtown metropolis with a trailer. Sounds like a small deal until you are in the position, I can tell you it is HUGE!
Hope this helps and gives you some ideas, it can be pretty fun from a systems analyst standpoint to design a system for a one man show.