I couldn't go to the link (blocked at work) but I have 400w lowbay MH's in my shop. Six in a 75 x 50. They put out a tremendous amount of light and I'm happy with them. Mounted at about 16' high. I have a row of 8' 2 bulb t8's down the middle for quick on/off lighting and a few more over benches...
I'm currently doing this in a 50x100 building. First 25x50 section is apt and rest is shop. I just put up an insulated metal building and am framing/sheetrock/finish the apt inside the building like any other construction project. I'm only at the framing stage inside right now. PM me an I can...