Hi Ken,
At one stage I had a sample of various Kodak Gel Filters I don't recall if they included any blues and not sure whether I can find them, but I'll have a look.
If it's for a trial, I could loan you a HOYA 80B 52mm screw in filter. Maximum transmission is around 85% at 400 nm (more than the Wratten47), but it doesn't cut off as quickly as the W47, tapering down to about ~20% at 650 nm. Used with a suitable UV/IR filter with enough UV response for you, it might be OK. Or you could use a Neutral density filter to reduce transmission across the board to get it to "look" a little more like the Wratten 47 filter's transmission curve.
Hoya 80B ....
Some other possibilities ....
Another possibility would be to use
only the Blue channel from a colour camera as the transmission for the Blue is fairly close to the Wratten 47. Take for example the ZWO183mc response....
Best
JA