Some beautiful leaves on those paphs you got!
I wish I was as crafty like you, but thank goodness they sell easy set ups here and ready-to-use shop lights.
I just recently put up a light unit as well.
Mine is about the same as yours, just one foot shorter, 4ft length and 18inch deep.
I have 4 T8 regular shop lights and some plants are getting bleached.
You have only 2 T8, so I think you should be fine as long as plants are not too close.
I grow most other paphs by the window with very strong light filtered by sheer curtain. I can still see sharp outline of the shadow cast by my hand over the plants, so I assume it's really bright. no bleaching of leaves there.
So I assume 200 fc is not an issue. just saying.
I grow cattleyas and certain dendrobiums together with my paphs.
They all do fine. I think multi-floral paphs can take over 3000 fc, at least that's what some books say.