You're right. Seems like the way to go and I did for awhile (some time ago).
Then I bought a light meter and found it didn't seem to be such a good idea after-all.
I'm not saying this is necessarily better at the top, but definately better (IMHO) all around. (I couldbe wrong,, but it seems to work well)
Here's what my theory was;
With the reflective top, end bulb light from 4, should equal a fair amount. Even higher lumens than other areas. Maybe not as high as one over top, but still stronger than the surrounding. with the bulbs off to the side the surrounding gets a greater percentage. But waite. CKLs have limited penetration! Need to be close! (Etc).
Noted also is the idea that new, fresh, growth doesn't actually need strong. Kind of in the same boat as a seedling in ways (maybe?).
Enter the Light Meter;
According to the meter, my theory was more correct than I realized.
Using the RapidTest 4 in 1, The center was still a slightly higher area of light. Surprisingly though, all around was nearly as bright down to 8" with this cab layout and the lights as they are shown. I'm certain the reflective materials have much to do with it. My light meter reading very closely approximate a slightly / hazy outdoor day with just these 4 bulbs. I will be changing them as we go along to increase penetration. Also have the ability to add 2 more in the oposing corners later.
Now, I don't know how it's going to work in the finishing flowering stages. But it has proven it's self past the mid point of flower already. Wasn't intended to flower, but the grow room wasn't finished as planed and had no choice on a prior grow.