Hello all I'm new here. I'm working at a local high school as their LD and we just purchased 10 S4. Most of our stock are the 360Q's which are up to 14 years old. Currently I'm running at 575 FLK. I want to purchase 3 or 4 different new lamps to try in these fixtures so I can replace most of them. I saw that there is the Ushio SPH 575 and also the GE-Thorn. I'm also not opposed to going 750watt if there is a decent lamp out there that will work. Thanks.