I always like to give them a shot of 5 PSI, and vent any air in the headspace. Then I give it another shot at 5 PSI just to seat the lid and everything just right.
If you don't have a fridge for keg conditioning, you might want to consider natural carbonation. 1/3 cup corn sugar with a pint of boiled water into each keg.
I would think with forced carb, you'd have troubles getting the CO2 to dissolve at those 'high' temps.