New set-up : Advice welcome

Hi all,

My first post here, so I'll make it a coherent one to make up for some of the random shit that may come later.

I grew a single plant around 10 years ago, and got about 3oz of colas without really knowing what I was doing. I bent the plant back a lot & ended up with a plant about 12" tall but 4 feet long, pegged out on bamboo. I produced lots of loose flowers & shoots, but that didn't matter because it was just for me - kept me in smokes for a whole year.

This time - let's just say I need to earn quite a bit of money in a short time, so I'm trying a more commercial approach.

I am just starting to convert my attic space into a grow-room. I've ordered 10 each of two indoor varieties (all female), and I'm going to build the growroom over the next couple of weeks.

Seeds are
http://www.cannabis-seeds.co.uk/prod...product_id/459 and http://www.cannabis-seeds.co.uk/prod...product_id/461

The plan is to germinate most of the seeds & veg them for 2 months or so, then switch to 12/12, with an aim to harvest in December. I also aim to keep a couple back under 24 hr to use as mothers for clones, though I plan to clone all the plants before they flower & use them for the second harvest. Ultimately I plan to use a 2-room system

I've ordered 4 quadruple 4foot flourescent ballasts (to start), so I'll have just over 500W of light.

I've read all the FAQs & stuff, but would be interested in any more specific advice - such as :

Does this light set up sound sufficient ? My back-of-a-fag-packet calculation gives me 40k lumens over an area of about 3 square metres. Obviously I can buy more if I look like I need it, but if this is woefully inadequate, I'd rather know now so I can plan.

Any hints specific to the varieties I've ordered.

What yield would you expect from this set up. Both seed varieties are high yielders, high potency

Thanks in advance for anything useful. I'm going to be away now until Thursday, so don't be offended if I don't reply before then.

Blessed Be