Last year i went to a dyno day at AVO held by the Pulsar GTiR club and i paid $35 for 2 power runs on their 4wd dyno.
As for A/F mixtures, they check those during the power run anyway as well as listening for detonation all at the same time.
I still don't see why brand new dyno rollers have to be set up for every car, if its a case of moving the rollers a bit to adjust for different chassis/wheel lenghts, it only takes about a minute...