Your vehicular deductions are sound, but the salt is of oceanic origin, rather than northern winters.
Ospho is my favorite rust treatment/ converter/ bare metal prep product, one can buy it in Ace hardware.
Using it with 99 cent store scrubbie sponges, or Ideally, scotch brite scrubbie sponges, and one can get rusty metal quite clean, degreased, rust free and promote maximum adhesion, of Paint/ epoxy, especially if they apply and scrub, then wait until rust turns black, then the next day, repeats the process.
One can also apply it, wait for the brown rust to turn black then scrape, wire brush, sand, chisel the black iron phophate, back to brown iron oxide below, apply more ospho with a scrubbie, wait for it to turn black, repeat, and eventually get down to bare pitted steel with enough applications It's weirdly cathartic.
While Naval Jelly supposedly does the same thing, I Much prefer the Ospho. It is very thin, spreads easily and penetrates rust deeply and seems to be an excellent cleaner as well, degreasing as well as etching and prepping for maximum adhesion. It lifts paint/primer, only when there is rust under the paint, at least in my experience, and this is desirable, to me.
---
My Vehicle has the ability to power a 12 amp tablesaw through a large pure sine wave inverter, via battery power alone, but I have decided I'd rather have lots of charging capability, opposed to huge amounts of Heavy battery capacity. I also refuse to carry a generator, mostly due to space concerns, but I despise the noise and don't want to advertise a Van full of tools, needing a generator. a 2500 watt inverter is tiny compared to a 2500 watt generator.
I manually control the voltage my alternator(s) is/are told to seek, in order to properly and as quickly as possible, recharge Thin PLate Pure lead AGM battery(s) which can accept HUGE amperages when well depleted, and seem way better off when they get them.
TPPL AGM's want to be brought upto 14.7 @ 77f when less than fully charged, held at 13.6v when they are. I modified an External adjustable voltage regulator with wires to my dashboard 10 turn bourns potentiometer. Voltmeters with sense leads right on the battery terminals, and Ammeters and battery and alternator temperature sensors allow me to achieve Ideal recharging by turning the dial. There's obviously more to it than this, ....but not in this thread.
I could relatively easily rig up a way to independently feed headlamps different voltage than battery/system voltage with a Boost or buck/boost converter, Via devices I already have, but the 13.6v to 14.7v range I choose for ideal battery charging, is more than adequate for the headlamps.
With a ten turn potentiometer and almost 6 full turns between 13.6 and 14.7 volts, I cannot really raise or lower voltage quickly, so seeing the brightness change from 13.6 to 14.7v is not really profoundly different from behind the wheel when changing voltage, as ones eyes adjust more rapidly. Believe me I've been tempted to stick my phone in various locations with Lux App going and change voltage and record some data, but in the end I am not all That curious. and the measurement device not that precise.
Years ago I made my own wiring harness for the headlamps using Sheathed Tinned Ancor 12-3, electing to run the grounds on that third wire to a ground buss on firewall near relays instead of body next to headlamps, as body grounds always seem to become troublesome and resistive all too quickly. I don't( anymore) skimp on copper, or terminations, or the tools to make them properly.
Having done so in the past, it saves no money and just wastes time, usually at the worst time possible to waste time.
If the battery(s) are well depleted the alternator(s) might not be able to quickly achieve and hold 14.7v at the battery terminals, at lower rpms, and it can be easy to overheat them maxing them out when parked, or really anytime below 25mph.
I will achieve proper headlamp Aim. The Load I carry changes, and can vary greatly. I will adjust headlamp aim accordingly, My fuel tank is 35 gallons and behind rear axle. A happy medium, is just my starting point. I count screwdriver rotation in 30 degree increments, and will go wider or narrower up or down depending on load or whether I am in long distance highway mode or mountain windey roads. The older GE nighthawks which failed, had a more obvious hotspot than the replacement silverstars, and were easier to tune for the conditions and good practice.
Pretty sure they are dorman plastic adjustment receptacles, 6 to 8 years old. I've ordered more, but re-engineering things for better function and durability is a past time of mine. Can't stop it. I could make a way denser insert drill and tap it, which would grab lots of adjustment screw , but have just ordered more Dormans, as I am currently quite busy with finish carpentry and rewiring/cabling charging systems on a large boat.
Such such a project is for when I am not so busy, and I'm likely to skip it entirely, unless the new ones strip instantly.
The other Hella V+, is ordered, as are Phillips extreme +130's ,12342XVS2+,
, and the dorman-like adjusters. I don't expect to drive much, if at all, after dark for a while, so the one headlamp with stripped adjuster, aiming way too low, is not an immediate concern.