A bit hard to tell due to angles and distances but it looks like the HID blows it away???
The Hid gives a more contentrated hot spot, the problem is that the VB-50's beam gets wider over distance and obviously dimmer, where as the hid generally tapers off to a point.
Personally i think the beam needs to be tighter on the vb-50, at most 6 degrees. this would project a smaller image of the die (square) and hopefully concentrate more lumens into a tighter beam..
I need to get this down on a moody dark 40m dive..
Packhorse, have you tried a sst-50 with one of the DX 44mm aspherics?