Great to join the UVP community

I'm experimenting with macro photography. I've been playing with several light sources to see the ultraviolet differences:
I started with Convoy s2+ with Nichia LED. This I found ok but I wanted something to compare with.
So, I moved on to Adaptalux UV arms. This had more blue tones which I wasn't sold on.
And now, I've modified the YN560 with Hoya U340 + Schott S8612 stacked filters. So far, I haven't captured anything I'm happy with. Images are dark with minimal fluorescence. Maybe my camera settings are off?!
Any advice with the modified flash will be gratefully received. Also, I'm using the Fuji XT30.