Hi Robin,
IMHO - I would suggest that for your purposes you try to get a bi-amped or tri-amped set-up regardless of how large or small the rig the difference in sound quality & separation is worth the extra £ & effort. of course you could just use the tops at smaller gigs as full-range
Have sent you a PM with list of gear I have in storage - just bear in mind that for the 3KW MaxSys rig I have you will need a large van (we carried the PA & 6 pce band including all gear & all members in a hightop leyland DAF).
If you don't have a van then I would look into PA hire with an engineer, then you have no up-keep costs, no depreciation & you don't have to set-up the rig!
anyway hopefully there are some items on the list I sent that might help you build a PA - just drop me a PM.
cheers,
Juice