LOL well I don't know about that but I am happy to help. So the screen cages are pretty close but from what I have read they can differ with some material blocking 30% and some 40%.
Where you really get the differences is in fixture type, how many bulbs are in it, and what type of bulbs... As well as a new UVB bulb vs one that is 6 months old. So it is one of those things where I just don't like saying oh do this in case yours is not like mine.
So I am really happy you got the solarmeter! Test it when after the bulbs have had a chance to warm up.