1978 KZ400 Headlight Recs?

I was riding my KZ400 down a dark state road and realized that though my high beam was on and functioning, I could barely see anything. I drive roads like these often, at night not as often but fairly regularly, so this is a problem. I bought one of those generic 7in LED headlights off of Amazon for the short term but it turned out to be significantly bigger than my stock unit and didn't remotely fit into my housing. So, while I'm conducting more research, here's my question(s) if anyone has any knowledge off of the top of their heads:

1) I would love to put a H4 unit like a Hella in there as a replacement, but I fear that it would be too deep for my headlight bucket (especially since it houses a lot of important connections in this model). Does anyone have any experience with an H4 unit in a motorcycle headlight, specifically a KZ?

2) Anyone have any recommendations for units that worked well for their KZ400? I'm leaning towards LED but I hate those bright blue headlights, I'd love something warmer or at least neutral (I have a set of 6000k in my car that I think is a pretty alright balance).

3) Has anyone had to make modifications to their retaining ring? The OEM sealed unit mounts in a way I haven't seen with other replacement lights. I'm also wondering if the KZ400 headlight unit is slightly smaller than 7in? (I know I should measure this to double check but I was in a bit of a hurry today. I'll have measurements hopefully tomorrow; but in the meantime it doesn't hurt to consult the moto sages if anyone's had a similar experience).

Thank'ee thank'ee as always for your time!

Just out of interest have you measured the voltage at the headlight before you start throwing money at the problem ?

just a historical fyi. there had been a halogen headlight available to fit the kz400 but the factory was closed after the Fukushima Nuclear disaster. and afaik. before the Tsunami. that was probably the best option available to fit the stock headlight bucket.

I put one of these on my previous '79 KZ400 and used the OEM ears to mount it:

speedmotoco.com/motorcycle-headlight-7-h...-overall-162mm-lens/
 

Just out of interest have you measured the voltage at the headlight before you start throwing money at the problem ?

Yep yep! Within a volt of battery. The problem is not so much that the light is abnormally dim, but that bulb certainly hasn't gotten any brighter since '78. So the problem is less that there's something wrong with the headlight and more so that I'd like to modernize this safety feature + make it easier to replace the bulbs/ light in the future. Now, admittedly, I got ahead of myself in picking up the first light since I had always been told all 7in headlight housings were all the same in the 60-70s... whoops haha. But that's going right back tomorrow.

just a historical fyi. there had been a halogen headlight available to fit the kz400 but the factory was closed after the Fukushima Nuclear disaster. and afaik. before the Tsunami. that was probably the best option available to fit the stock headlight bucket.

Ohhh that's interesting to know! I know there are some repros available but I think moving away from the sealed beam is my preferred move.

Nerdy wrote:

I put one of these on my previous '79 KZ400 and used the OEM ears to mount it:

speedmotoco.com/motorcycle-headlight-7-h...-overall-162mm-lens/

I think that one should work great, thanks for the link!