Attic grow help

If i was to plant a seed in a pot in my attic how big could i get a plant with 1 or 2 of those big CFL's?

What do you mean by 'how big'? Heighth should not be desired in your instance, but it's tough to keep plants small and bushy with CFL's. You need to keep the CFL's right above the plants so they don't stretch. If they stretch, you'll get spindly plants with small buds. If you keep it short and bushy, your buds will be more filled in and the plant will be stronger.

So, your plant can be big, but it all depends on placement of lights, nutrients, etc... Do everything right, and you may just get a nice plant with a decent yield.

The Q is not how big you could but how big you should because with CFL's it is like this: more lamps equals more growth... anyways with two 45W CFL's you could get a plant going... just remember to switch to flowering (12/12) early (in first 20 days)...
You should read Buds 4 Less book