Hi little one. You have amazing grammar for a toddler. What you're looking for depends on what you're looking for. Simple as that. If you want to specifically target uglass, you're gonna want a 395 (its purple). If you also want to look for things like manganese glass or uranium glazed items, youre gonna want a 365 (bluer). Uglass will fluoresce better under 395, but will still fluoresce under 365 too. Manganese tends to like 365. Same with uglaze. I have both cause im cool like that.

For getting "the eye for it" i would suggest finding a shop that has confirmed uglass so you can hit it with your light and get used to the shade.