LED distance from canopy

Hi there.
I'm planning my next grow and i wonder if you could help me with few things.

I'm going to do SCROG, one plant in DWC.
I have about 30 cm (1 foot) of vertical space above screen for lights and colas to grow.
Assuming that colas will be ~15-20 cm tall (6 to 8 inches), that leaves 10 to 15 cm (4 to 6 inches) for lights.

I'm thinking of getting a Blackstar 180w LED. From pictures it looks like it's about 3 inches thick, that leaves 2 to 3 inches of space between top of canopy and light, is that going to be a problem, is there going to be any bleaching?
If not, how about 240w model instead of 180w?
If 180w can't be that close, how about Blackstar 100w round one? I could fit 2 of those. It uses 2w diodes unlike 240w and 180w which uses 3w.

Also, is flowering model ok for vegging or i would be better off with some 6500k CFL's for filling the screen?

Also, with screen size of 30x50cm (12x20 inches) is yield of 5oz dry with those lights realistic? Assuming that strain is average to high yielding hybrid and enviroment/nutes/whatever are fine.

Thanks for taking the time to read this and any help is appreciated.

The 3w will def bleach especially if they are 60 degree. I find 10-14in is the sweet spot for my 3wchip 288pc 864w (draw 600w) that is with 60degree leds tho. Assuming you dont run into any issues growing you should expect 1g/watt with any of the lights you mentioned you should pull more then 5oz.