I think you can get more wattage with CFL's in a smaller space than regular long tubes, but I don't know what that would do to your heat issues. I'm just not knowledgeable enough on flo's anymore to give ya an informed answer, sorry.
You're already on the upper edge with your heat, though. I've always been of the mind if it ain't broke, don't fix it. Personally, I'd just replace the tubes with new ones and then decide as they grow when more/different light would be needed.
As for watering, I always just stick a finger into the soil (without fucking with the plants) and if it's dry up to the second knuckle, time to water.
Seems that overwatering tends to be an issue with some folks just starting out. Cannabis likes their feet dry, it promotes root growth as they look for the moisture. Stronger root system equals more vegetation. More vegetation equals more buds.
Knowing your ph is pretty important, unless your lucky to have good PH naturally with your water. Helps diagnose nutrient lock up and other problems that may arise. If money is an issue, you can just buy one of those PH test kits for aquariums and test your water's ph, or go with a better soil PH meter if money isn't an issue.