Joe, I'm not sure about Arri's but I've been putting 1k bulbs in Mole's designed for 750's for 25 years. So far they've not broken any more frequently then any of my other lights. Chances are you'll be fine but the lamp probably will get hotter than with the 300's and the switches will need to be replaced more often. Jim
James,
Mole is what i call meat locker technology.
Great stuff, but I'm positive some of their designs are 50 years old and I'm positive I've rented from Sony (Columbia's) electrical dept. lights that were used to shoot gone with the wind.
Studio's never, ever though anything away.
This grip rental cart was originally used in WW II to care ammo casings and is heavier than anything you'd ever put on it.
Arri's are tough, I love em' but I'd be careful not to go too far without a a bunch of good fire extinguishers on board.
IMO
BC