Yep Sylvania CWP. If the Hg starved behavior becomes a frequent issue I think I'll be switching over the GE, but the CWP lamps are $2.99 for a pair versus $6.98 for GE EcoLux F40CW lamps. If I'm not getting payed back for the lamps I don't want to spend over double the price for a lamp that I won't be using. and I can't buy in bulk since I can't spend large quantities of money at once since I'm on the "high school budget" (i'm sure you know where i'm coming from Andy) so I have to buy the exact amount of lamps that i need at the time i need them. I currently have one GE 3500K lamp, two GE f40CW lamps, and two Sylvania CWP lamps (removed from the RS shop lite) that will be used at my great aunt's if i can swap out a pair of GE 35W F40CW lamps, and Sylvania grow lamp, and i THINK two blackenders in a preheater in the garage that is wall mounted with two F40T12s mounted end to end in an 8ft fixture with a reflector.
As long as the odd CWP behavior doesn't affect the ballasts at all i'll keep using them.