SolarSystem 550 and coverage questions

So I just jumped on the bandwagon for these newer SolarSystem 550's... Growers' House has their 15% sale ending today and add their membership deal for another 5% off... I got tired of pondering DIY and it seems the prior vendor I used (A51) never has product in stock anymore... Checked soooo many times I gave up on them.

I'm initially going to try a pair of these SolarSystem 550's for covering a 4x4 area, with the prior runs being on 3 x A51 RW150's (first gen) and really only covering 2x4 in that case - the lights were hung 3 wide with the longest length running perpendicular to the light bar... it seemed to give good coverage I'd think.

So I'm wondering what to expect... Assuming prior was 150w x 3, so call it 450w... versus what should be 400w x 2 so call it 800w...

Is 2x overkill for a 2x4 and I should bump the sqft up to 4x4? I wanted to hit a high PAR without being wasteful and going past the point of diminishing returns... Otherwise I may stick with the 2x4 footprint for this pair and if it goes well invest in another pair for a full 4x4 coverage...

Anyone seen journals with these yet? Any other owners who can give 1st hand feedback?

ive been using them for years the latest osram models really pack a punch

2 of those (800W) for 16 sq ft is a lot... hang them at like 30" and you should easily get a 5x5 out of them

even a cheap light meter is your friend to get even coerage but 50W of osrams a square foot will only stress the hell out of anything within 18"-24" of it

Start a grow when you get them going please.

Also running all white cobs might throw off the programming those lights have for better plant growth.