I sometimes clip the snare channel too, just small bit seems to sound good sometimes.
I also use the EQ to boost for guitar solos. I usually put back in the high mids I cut out to make room for vocals for solos and pull them back out when the lead is over.
I find I rarely need overheads at all. I mostly work in small places but even in a large place with 500-600 people I didn't feel I needed them and didn't use them. Sometimes a hi hats mic is needed and depending on the band a ride mic, but generally the bleed from the cymbals into vocal mics is more than enough.
Jipchen, it sounds to me like those gigs you're playing are thrown together. The engineer should be the first person there to set up the PA gear and it's in his interest to have ye sound as good as possible. I always talk to a band when they're setting up and will try help them set up in a smart, tidy, sensible manner. Not all bands have a clue what they're doing and alot of guys will have their amp blasting at their legs without thinking about it. I've had bands move monitors further away from them becase they felt it was "too close" and that they'd be blasted out of it, then complain they're not hearing enough from the same monitor!
You shouldn't expect helpers/stage hands though, it's very much so the norm for the bands to set up the gear. You shouldn't have done it all by yourself, whoever's sound checking first (usually the headliners) should set it up with other people input if they need something specific for their set. Usually whoever owns the gear chips in but you stated it was rented in this case.