Humidity is never a problem unless it hits 70 or over, i have an aircooled light but i found it made little difference to barebulb so i run it without the glass.
Uk Summer night temps are fine for hps, to be honest as long as heat cant build up you shouldnt have any heat issues regardless of temps.
Make sure thermometer is not under the light, this is a false reading caused by radiant heat, we only want to measure ambient, transpirational cooling can deal with more than we give in radiant heat.
Wider area light futher away, canopy more open to hit lower buds more airflow.
Never blow wind on plants, quite un natural and most of all numero uno heat resistance comes from tip top healthy plants.
I just keep a window open so no build up of heat and my plants are sweet most summers