Accumulator, can you do a video shoot of the BHB foamgun combo?
Nope, sorry. I don't do the "digital images on the internet" thing nor do I shoot videos (I know, everyone else does it with their phone).
You have a bhb in one hand and a foam gun attached to a garden hose in the other?
Yeah, that's basically how I do it.
For the umpteenth time

...yeah, I know, I really need to do a proper write-up of my current wash technique. But here's a quick version:
-replace foamgun's pistol grip with a 90° shutoff which can be operated by thumb (just works better overall IME), use strong setting on foamgun, have gallons of 6oz : 122 oz shampoo mix on hand
-spray foamgun output on wet panel and saturate BHB with it too (or dunk BHB in wash bucket..but get it *WET* with shampoo mix whichever way)
-foamgun in one hand, BHB in the other, move BHB across panel in short, interrupted "jiggling" motions while spraying foamgun output at point of BHB-to-paint contact, on the side towards which the BHB is moving. Do small areas, not whole panels
-pause to rinse area, dunk BHB in rinse bucket (possibly not necessary, but safer) and rewet with shampoo mix, and inspect panel to see if it's clean
-repeat as needed until panel appears clean
-repeat with mitt/foamgun combo or wash with rinseless wash solution using Garry Dean Method (used properly, IME the BHB is a little too gentle to get things perfectly clean)