At the crux of the issue is one big thing... nearly every Marine is a leg, but a leg that can swim in some fashion... so you're sorta fucked in that manner.
Wait, hear me out, it's a friendly (while being truthful) chiding because of one specific thing.... parachutists retention straps. Using those on the ugly old K-pot effectively turned the old 2 point chinstrap into a 4 point system, which would keep your dome up in place while wearing NVG's. They are not designed to be easily removable, you take off the rear screw and mount it inbetween the interior helmet band and the kevlar itself... so you can pay to play that way. You could always toss a set on your helmet, they tuck away rather unobtrusively but if your TL/SL/etc enjoy rubbing their grubby little dickbeaters all over your kit for repeated unnecessary inspections then they'll see them. Cheap piece of kit, but given that you're apparently somewhere you're being forced to reg-skirt it's most likely outside of your capacity to use.
Next thing to check out and try... As newly issued, there are rubber bumpers made by the lowest bidder that are part of the mount as affixed to your helmet. The upper solid rib and lower latch interface into 2 points in the mount itself, with forward/back play depending on those very little, very shitty, and very undependable bumpers. A used mount 9 times out of 10 either has shot bumpers or they are flat out gone from the mount plate due to them being a simple nipple based interference fit where they get jammed in with a spiked end through a hole like a blind rivet of sorts. Layering 100mph or electrical tape (I preferred electrical) inside of the mount itself, in the center portion towards the bottom, will restore a solid connection with some give for actual latching while still allowing you to sustain an otherwise immobile mount structure between your dome dome and whatever you're attaching as NVG's.
Addition of a bungiee is another method to make sure it doesn't wobble or at least wobbles less, but adds fun of its own since if you aren't using a helmet system designed with it in mind (as well as trying to skirt regs, it seems) you'll have to figure a way to attach said bungiees to the flipmount, then somewhere that it won't be a bother on the helmet. The foliage holes on the cover itself come to mind, but you also induce strain and as such might render the cover unservicable unless you can rig something up. Perhaps taking your helmet cover to a sew shop, having 2 foliage holes reinforced with a stitched loop of 550 that has it's running end going aft along the cover to it's sister loop on the other side of the helmet. Then you could hook bungiees into that without worry of it going anywhere... theoretically. This would still rely on whatever mechanism (MICH'es it was hook/pile on the ends that we'd put the pads over) holds the cover onto the helmet. Wouldn't be hard to make it something easily removable so nobody shits a brick since it would only be on and used when you actually have your NVG's on.
Use of the eyecup also can help in reducing wobble, but is variable in actual utility due to no anti-fog really being good anti-fog and the associated issues with a relatively sealed environment with a glass lens you want to keep unfogged being in direct proximity to a permanently moisture producing organ such as your eye.... and that's totally ignoring environmental aggrivations such as evening dew, the rain god being pissed for being called a pussy again, a Rain Turtle having been drawn and watered, or what ever else environmental aspect (to include COC derpage) decided to shit on the Infantry that day.
The necessity of a counterweight with a 14 is minimal at best, I only even used a counterweight PERIOD the few times I used dual tube systems in Iraq, and then it was the battery pack itself anyway, so it served a primary purpose with the tertiary nice bit of a counterweight. That was for the entire portion of my lifetime I've spent under NVG's which while tiddlywinks to some of the pricks that roam the halls around here, still at least dwarfs the time in service of an E-1 freshly assigned to his first duty station. To be honest, I would rather have something of utility such as a battery pack or a strobe, or SOMETHING useful rather than just adding a weight for sure.
Your best bet if you've got an absolute hardon for a counterweight and doing some neck PT, your auxiliary brain housing group installed on your dome, lying on your rack with your nug unsupported doing up downs left rights etc, isn't something that sounds like a good time..... while retaining some real utility IN that counterweight... would be using 100mph tape to put about 4-6 batteries that are ziplocked and flat, under the camo cover up on the outside of the helmet in the rear. At least then, if someone shits a brick because you have a bit of a lump on your dome... you can attempt to play it off as what it really is. Emergency batteries on your kit for your NVG's and associated night engagement systems.
Hope this helps.
You could always just suck it up and then go Recon or something if you want to maintain wear and care of your EGA's, or otherwise jump ship to try to be highspeed where budgets are bigger and so is your paycheck for it ;)
