Lighting fixtures

[whispersinmyhead]

I am having a hard time finding a 36" t8 fixture for a crossfire type enclosure I am planning. I live in Oshawa Onatrio, and can only find t12 fluorescent fixtures. Does it really matter? I know a t8 is the same size and pins. The wattage is lower so it may get too much power... I can't even seem to find a t8 ballast to replace it. Any help is appreciated. Thanks.