The adventure continues!
I'll get the small stuff out of the way:

I took a look at the grav charges from JJ Industries. This is the raw kit, resin black topper, and appears to be acrylic base and red acryclic dome. The top pops out exposing the magnet (which connects to the plate on the belt) and room for small LEDs or some contraption. All I did was wrap a bit of painters tape around the base to snug up the fit so it doesn't open easily. I may do lights, sound would be cool, and both are upgrade worthy one day.
This next bit is more my observations and reflection on what I just did and why it did what it did. It was my first time using this stuff, so perhaps my next go around will be something different or cut to Alumaluster like I probably could have. I could also sand this back and repaint, but I digress. I'm going to finish the build with the current progress. Huzzah. If you're interested, here's my success and failures, however you want to view them.
I enjoy the simplicity, low cost, and high reward of graphite powder.

With every chrome, clear coating and protecting the finish is the big question. The issue lies in the clear coat fogs or dulls the reflective finish and polish of the silver and turns it a dull gray. There are paints and finishes that are intended to work together. There are finishes that preserve colors better. There are lots of options. A little internet research led me to a video that compared graphite clear coats and the take away was Spraymax 2K clear coat was the winner. With no application tips or tricks, I was off to the races to figure it out and document for science.
I'm torn on the look, but follow along and I'll attempt to explain some pros and cons.

Right out of the gates, the graphite color got darker upon application of the clear coat, BUT, the high gloss reflection remained. This is a win. The mirror remained, but it got darker... For the record, I put down a pretty smooth heavy top coat where it was an even gloss across the surface. I started off further and it misted the clear coat, so I got closer for better coverage. Big take away was the gray remained in the finish (dulled from the high polish of base graphite), and so did the reflection.

It's still a close match and I reapplied a graphite layer on top to brighten it, but to very very little effect.

Click image for video here:

Here's the best representation I could get of the helmet in the garage. It looks like the graphite was added into the top coat, like it mixed with the spray. I can see evidence of color blending, though subtle, so I wonder if it combined since it was powder and liquid:

Indirect and direct sunlight check:

Here's the rest after the clear coat had set for about 30 minutes:

And here's the same set, after the sun went down and just garage lighting:

It looks like it's going to work. I think the alumaluster route would be a brighter finish under the clear coat - and that 2k clear coat is great now that I've used it. $30 and once you crack it, its only good for 48 hours tops. But it did a great job, and I've used a few other clear coats in the past. I'm satisfied with the finish of this method and I'm happy that my graphite top coat is protected my a glossy finish and held it's mirror despite losing some luster.
Here's some theories I'd be interested in trying, or if you try, let me know.
I tried reapplying a graphite layer to the top clear coat, hoping the graphite would pull back some of its luster once I polished it. I did one coat and didn't notice a difference. I hear doing a graphite coat then another clear coat, then a graphite coat (buffed) will do a good job, but I'm stopping here. I like the reflection I'm getting and from my test, extra coats don't appear to yield the results I want. I'd just go alumaluster at that point, but this is an inexpensive alternative by maybe $80 and an airbrush kit.
The theory is this: Black gloss gives the mirror finish and graphite gives it that metal luster. I wonder if you clear coat the black gloss and protect it, then graphite on top to polish. You should keep that bright graphite finish with a protected base coat. If you need a touch up, a bit of graphite and buff. I found graphite, once applied, didn't really come off after buffing, so this sounds like a viable method to keep a high polish finish, but may require maintenance.
After all of my contemplating, however, I decided to protect the graphite layer. I had one can of fancy clear coat and if I was going to sand everything off, it was going to be after I confirmed graphite failed under the fancy clear coat. So far I appear to be aligned with things, but also feel it could be improved with a brighter finish, but I guess in the sun it would be like, KACHOW! I dunno. I'm still torn, but you be the judge.
If I go the black and gloss layer method, any ol' gloss clear will suffice since it's only protecting the black. Graphite would do the work regardless of clear.
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if you try this, let me know. I'm letting the 2k clear coat cure for a week and will pick up the armor again this weekend for airbrushing details! whoop whoop.