How close can LEDs be to canopy before bleaching occurs?

Here's my issue. I plan on using a double sterilite bin for my grow space. Total height is just under 3', it's like 2' 10". I want to do a 1 plant 12/12 grow and maybe expand to two plants based on the size of the first grow. I will be using a bed instead of a pot for maximum space. I'm looking at either the PG-180, the BS240 or depending on how close I can put the canopy to the LED a BS180. I know the PG-180 has the most power out of the 3 and it's what I intend to buy. I just don't want it to be too powerful, end up bleaching my plants and me not having any more room to raise it. I'll of course LST and possible supercrop.

So pretty much my question is: How many inches from the panel will the plants begin to bleach.

It's usually about a foot or greater depending on brand if you want a decent coverage area, but generally speaking the lower the wattage of individual diodes the closer you can put them to your plants. Hypothetically you could buy a bunch of those red low wattage panels (13or 14watts) off of ebay, and line your room with them, or even buy that red led strip lighting and make custom reflection to cover it's wires, the plants could literally touch them and not get burned. Plus with proper reflectivity they are brutally efficient. You would still need to buy top lighting, but you could save some cash by buying a giant 100watt 3000k floodlight for the top of the cab. It will grow like a low quality HPS by its self, and with any addition of red lighting it would grow quite well in a small cabinet. Quite well indeed.
Just some thoughts from someone who was once in your position
Sincerely,
ILovePlants

I supposed I could keep the plants under 2 feet if I used a gardener's bed and if I go 12/12(nvr gone 12/12 before though), but that's still cutting it pretty close. I think the 2012 BS180 uses 3w diodes. I know the PG180 and BS240 use 3w for sure. DIY would probably suit my needs, but I'm really bad at it. Not that I lack the patience(well maybe a little), but I just suck lol. Really want to go LED because 100F+ degree weather this summer kicked my ass. A/C can only cool so much.

I would say 12 inches is good or 8 inches if you have a fan blowing between the light and canopy

I've had my PG180 as close as 4" to one plant without bleaching while another could not handle 8". So yeah, 12" is safe for the plant as it gets older, but as far as 18" in the early stages.