I'll have to check on the brand and wattage, as the packaging went in the trash.
There should be information on the base or neck of the bulb, sometimes on the apex.
The temperature is warmest on the end where his rock is, and I've noticed he goes back and forth in the tank to thermoregulate.
Invest in a couple of accurate, quality thermometers, so that you can place one at each end to monitor both extremes...digital ones with probes work well, but mind you keep the wires out of tortoise reach.
Perhaps you could suggest a healthful diet for him?
This one works well, but I would avoid kale and cabbages altogether: http://www.russiantortoise.org/russiantortoisediet.htm
I understand you have a large menagerie.
Not any more...I one time I ran 70 aquaria, had 140 reptiles of assorted types (including 35 tortoises), 2 parrots, 3 ferrets, and two cats. Over the years, I have had literally thousands of animals of all descriptions under my care, both personally and professionally. Currently, my 'menagerie' consists of 24 assorted tarantulas, 3 red tegus, two cats, one green-cheek conure, one bearded dragon (actually my daughter's), and 3 aquaria (one planted FW tank and two mini-reefs).