Folding Screen top issues

So i have Fred in a 40 gal breeder, was originally going to do exoterra but the 40 dollar petco sale got me... anyway, i have a hinged screen top, all metal, folds in center to help with access. UVB is mounted atop screen in reflective hood with basking light adjacent to it. I know optimally heat and UVB should overlap, however due to the screen top i can only place them side by side... question is really about the UVB i think. I usually see measurements and diagrams showing relative UVB intensities projected downward, however not many showing how it is affected at the ends of the lamp, so at the lamp holders and diagonally downward. I know light bends and so i know it doesnt just come straight down but how much will actively be radiating diagonally? because the light from basking and UVB will not technically be overlapping much, how can i modify set up so basking will lay underneath uvb zone? Let me know if my question makes sense.

Ideally you'd want to cheat the UVB light over to one side to provide a gradient away from the bulb but if there isn't room, perhaps you can set it at a diagonal. From what I've seen, the UVB exposure drops off quite a bit as you move to the side of the bulb (which is OK - it provides a gradient) with the highest intensity being directly below the bulb.
Here's a chart with some readings I took on an T8 bulb. It's not the same intensity that you'd have with a T5 but it gives an idea about the dropoff you'd see as you move away from the center of the bulb, both to the sides and downward. Keep in mind that these readings were taking using a Zilla Slimline fixture that has a reflector built into it. Without the reflector the readings directly under the light would likely be less intense and the dropoff to the sides would be less drastic.

thank you coop, i'll use look over it