Before I get hit with a thousand models; some of my requirements:
1. Minimum 950 lumens; more would be better.
2. Not too tall profile; should be equal or less than my last set-up.
Niterider Lumina Flare.
3. Less than US$300(light, battery, helmet mount).
4. Single unit; no separate battery pack.
5. Can be operated while wearing winter gloves. On/off/toggling
between lo and hi.

Background:
Was happily using a Niterider Lumina Flare(650 lumen rating) for 2
years. Together with a Lezyne Mega Drive on the handlebars; output
was enough for my needs. Helmet mount had a ratchet action; allowing
me to point the beam lower(or higher). I bought the helmet mount for
Lezyzne and didn't like it. Profile was too tall; locking ball adjustment
for beam angle seems crude. Can easily control the light even with thick
winter gloves. But I lost it in my last move. Still have the helmet mount
on my helmet; and probably the bar mount somewhere in it's box.

Can go with the Luminna 950 boost as a replacement. Cateye Volt1600
looks interesting. But helmet mount profile seems tall. any other models/brands
I should consider? Thanks in advance fellow riders.
Large pizza; tiny bike - challenge accepted by 1nterceptor, on Flickr

All in one and over 950 lumens is difficult. By the time you get above that, its most likely too much weight. 950 boost may be your best bet since you already have 650. But be aware the 950 lumen rating is 40 minutes.

Thanks for the input. Yes, I'm aware most lights don't last long at the highest setting(s).
I usually alternate power levels while I'm riding to maximize run time and power. I'll
have it low or off on lighted paths, medium on familiar roads and high in daytime traffic.
This is why I need controls/buttons I can operate with gloves while riding.

At this point, it looks like I'm going with the Niterider Lumina 950 Boost, since I already
have a helmet strap and I'm happy with how it works. Would have been interested in other
riders' review of helmet mounted Cygolite Metro 1100, Cateye Volt 1600, etc.

Here I have a generic Magicshine on my helmet. While it was powerful and I'm able to
operate the switch even with winter gloves in the rain; I didn't like having to place the
battery pack in my pocket:

Zebralight H600w

H600w Mk III XHP35 Neutral White 18650 Headlamp

Check out the Serfas E-Lume 1100 or 1500. Well made, dual LEDs, single button on top. They come with a handlebar or tube mount, but Serfas also offers the S-Unihelmet mount. Not sure whether it offers the adjustments you want.

Serfas lights use a slide in/out mount with a springy retaining clip, similar to a camera flash hotshoe. My older Serfas light has been secure on the bike. Seems like it could be adapted to a helmet.

My method for adapting a light to my helmet is to nestle the light into a vent, then scoot it forward and backward until it's aiming where I want with my head in a natural position. Usually I keep it aimed slightly downward to avoid blinding other cyclists and pedestrians on the MUP. When I need more light ahead I just tip my head up a bit. Works perfectly when I want to give an errant driver the stinkeye. I just look at them and the brightest part of the light is on them -- seems to get their attention.

My lower power helmet light comes with a simple rubber band strap, but it's only 300 lumens (nominal, actually not that bright). For other lights I'd just rig up a homemade velcro strap and elastic bands.

There are also 2 cell 18650 packs that could attach to helmet.

https://www.action-led-lights.com/co...2-cell-battery

Thanks for the recommendations and advice everybody!

I still have a Lezyne Mega Drive on my handlebars right now.
And I have a Blackburn 2'fer on my helmet. Long term loan from
my brother; but as you can imagine from it's size -it's very weak.
So I'm not in a rush to get a new light right away.
Brooklyn Bike Rave by 1nterceptor, on Flickr
I just clipped one of my smaller flashlights to the Niterider Lumina
helmet mount. Just a temporary fix/experiment. Olight S1R Baton uses a
unique charging system; end of USB plug attaches to light with a magnetic tip.
Didn't get a chance to ride with it yet:
Olight S1R on Lazer 02 by 1nterceptor, on Flickr

What kind of conditions do you ride in that makes you want so much light?

New York City traffic. I run at least 2 front & 2 rear lights.
In case I forgot to charge some and/or 1 malfunctions or flies
off the mount on a deep pothole. I want bright lights because
I use them in the daytime. Here you can see my flashing light's
beam bouncing off some cars:
And yes; I have my lights off or on low on shared paths at nite.