It's about the same physical size as the one I use. Mine sits in a fairly large dome suspended above the enclosure. You may need to adjust the height, dim the bulb, or change wattages to get the proper temperature gradient. This varies between enclosures so will require some testing.
As long as it's rated to handle the wattage it should be OK. Those bulbs have a built in reflector (PAR means parabolic reflector and BR means bulge reflector) so the outer dome isn't as important for directing light.
I'd make sure the fixture is rated for slightly over the bulb wattage. I've ran into longevity issues with using bulbs at the max of the rated wattage for the fixture.