well for me, like the others said, if the thermostat is working properly, even if you set to the coldest it would still disengage. so no need to worry what setting you use. i normally set mine to the coldest at first then pag malamig na depending on the weather, i set 40-60%.

my car's compressor usually disengages 10-12 secs at fan 1 at coldest setting, then 5-7 secs at fan 2. mas tipid sa gas if you have it a lower thermostat setting, syempre the rpm at idle is higher when the compressor is engaged compared when it is disengaged. bakit nga pala ganun yun? is it because of the load placed on the engine when it engages?