Lumen and lux

I have been reading up on what amount of light is needed and I could be way off but this is what I am going with in regards to flowering.

I have read 10,000 lumen are recommended. I believe this is per sq. foot. So, Lux = Lumen/meters squared. Foot to meters is 12inches / 36inches = 0.33 meters; sq. meters = 0.33m x 0.33m = 0.11 sq. meters. So, 10,000 lumen / 0.11 meters sq. = 90,909 Lux.

From what I have read just from searching around, 90,909 Lux may be on the high side of required light to flower. This amount is roughly the same amount from the sun on the earth at noon and may slow grow? I think it has something to do with heat stress??

I also have read the 25,000 to 50,000 lux is good for growth.
I was planning on 8 CFL at 42 watts each 2700k, 2600 Lumens each in an area of width 0.66m x depth 0.66m x height 1m for flowering.

8 cfl x 2600 lumens = 20,800 lumens.
Lux = 20,800 lumens / ( 0.66m x 0.66m) = 20,800 lumens / .44 meter sq. = 47,272 Lux

I am not really sure how distance from the CFL's come to play in the calculations. I am assuming this will be with the plant being 4 inches from the cfl.

I am guessing that the farther away from the CFL's, a proportionate decrease in LUX will occur. But I really have no idea.

As you can tell I am fumbling through all this in hopes of my first grow.

Am I at least in the ballpark?
Thanks

Man, You have all the right formulas, I'm pretty sure of that... But sit down a minute, fire up a bowl, and let me introduce ya to the redneck rules of growing weed...

RULE #1 - for every 100 watt of Hps you cover 1 square foot of area so that said a 1000 watt will cover 10 sq feet. figure out the area of the rom you want to fill with light, do the math and smoke another bowl.

RULE #2 - water only when your soil starts to feel dry to the touch

RULE #3 - feed every second watering

RULE #4 - visit every day

Sure fire way to grow weed w/o a calculator..
Good Luck with it and I'll be following this post cause it would be way cool to know the answer but its way easier to let some1 else do the math .

Thanks for the reply.

THe only problem I have with HPS would be the hieght of my growing space. It is only 3 feet high and from what I can tell you need to keep HPS farther away from the plants. So, I am going with CFL to maximize growth space.