I think probably something like an R44 or DR680 is the way to go if you can afford it. That's the way many of us run most of the time (2 mic + 2 SBD). Having the ability to record the AUD and SBD separately and mix them at home is worlds ahead of mixing on the fly. Sometimes you decide to go 90% AUD and 10% SBD, other times it's the other way around. If you were mixing on the fly you would be guessing.
If you had a stock UA-5 and a stock R44, I would just use the inputs on the R44. I don't know that either is a lot better. If the UA-5 has an Busman or Oade transparent mod, versus a stock R44, I think that's where most people decide to run the UA-5 in front.
Depending on the room, put 2 mics close to the stage, or on stage. Some times you can clamp to the light bar, or an overhead beam that will put you a few feet out from the stage, or you can also go stage lip or onstage at something like knee high or waist high. Being low will give you a little more pickup from the bass guitar amp, but can pick up a lot of what is in the monitors (which may be good or bad), and you have to worry about some wookie spilling beer on your mics. If you go overhead, you don't have to worry about the wookies, but then you tend to get less bass guitar and more drum overheads.