The Kessil fixture is like 2" by 3". It's the size of a flashlight as far as I know. My T5 fixture is about 10" off my canopy as you recommended.

I'm going to shine the Kessils from the side on a downward angle(maybe with a coat-hanger or some kind of wire with loops, or velcro). I'm only growing one plant so it should be fine. I'm not, and never will go for a UFO because I have read many reviews that say they have bad power driver units and once they go bad, you can't replace or something? I did some research on making my own 660nm 150w light with 5w single chip LEDs. The LEDs are about $8.50 a piece, and the driver is over $100. I think I will stick to the Kessils for now. LOL at least they have a warranty if the driver goes out.
Going back to the HPS subject from earlier,
Although HPS lights emit a yellow dominant wavelength, it is still classified as red light.
I did a RGB analysis of my HPS+HortiBlue room. Here are the results,
View attachment 2055459
It seems like the HPS + Hortilux Blue combo would be a good Veg combo, but not a good Flower combo because the red/blue ratio is wrong. I think I will try the HPS + UVb idea next time instead of adding the Hortilux Blue.
Next I did a RGB analysis of the HPS light alone. The results are interesting. Pretty much sums up why HPS lights work for flowering. They work because the red to blue ratio is correct, not because they have the wrong wavelength. It shows how the red/blue ratio is almost more important than wavelength.
Proper wavelength + proper ratio = perfect buds
Here are the RGB results for the HPS light by itself without the Hortilux Blue,
View attachment 2055518
As you can see the addition of the Hortilux blue adds quite a bit more blue.