Here's some more LED headlamp comparisons.
first, the 5th Gen CDRC 6V LED bulb tie-wired into the BPF reflector in the A10 (with the A10's aging battery). it is non-destructively centered by a former. It protrudes less into the headlamp shell than if using a H4 reflector tho not by that much ***. I haven't driven enough at night to comment much but its brighter than the double dipper, reasonably focused, but also more glarey to traffic and gets a lot hotter. Compared to in a H4 reflector it is much less focus and dimmer. I forgot to take a photo of this bulb in the H4 reflector and its now wired in and staying there, so one comparison missed. one day I might reconfigure stuff in the headlamp shell and get an H4 reflector for it. these LED bulbs also have regulator boxes to fit in there.
second: the H4 CDRC 12V 5th Gen LED in an H4 reflector in the B33. its awesome - bright, well focused, crisp, low glare for other traffic. definitely the best of the lot.
Third: a cheap H4 LED with the fan inside the H4 reflector, which I thought may keep the wiring/ammeter cooler. rated 4000lm. problem is its enormously fat (would not fit into the BPF) and the plug protrudes a long way out the back. and I'd hate for the whiney little fan to die on a country road at night. Its bright, but much less focused than the CDRC bulb (and no where near as expensive.)
***so how much do the h4 bulbs and their plugs protrude into the headlamp shell? funny you should ask: the h4 shape is more convex than the BPF but half this is out the front. measuring from the back of the glass rim (where the W clips attach it) to the back of the plug or bulb:
BPF reflector with BPF bulb and plug - 72mm
BPF reflector with H4 6V CDRC bulb tied in : 84mm
H4 reflector with H4 6V CDRC fitted: 96mm
H4 refelctor with the H4 12V bulb (above) with fan inside the headlamp shell - 93mm as the big plug is directly on the back of the bulb