Blowing voltage regulators

A bit of an update here, going to be a bit longer so bare with me.

So I installed the new VR and the car charges again. I noticed on the ammeter that when pressing on the accelerator when the engine is idling the ammeter pegs all the way to the charging side for about 0.5s then returns to normal value. When I was cruising down the road the ammeter was stable a bit under the halfway mark on the ammeter, but it also pegged the same way when for example accelerating from an intersection.
So I decided to get rid of bad connections at the bulkhead with the MAD conversion and installed an volt gauge instead. Now I have an overcharging problem, at first the needle was jumping between 14-16 volts at higher engine speeds and at idle it's dead solid at 12. I cleaned all connectors and grounds that I could think of and insulated the soldered splices in the MAD conversion even more and that ended the fluctuating and gave me stable 15v of charging. Again idle is fine at a bit over 12v.
Now I'm out of ideas what to try, grounds from battery to engine block, block to firewall are cleaned and showing a ohm reading of 0,3. The VR is properly grounded, bulkhead is clean and the VR sees about the correct voltage, have a drop under 0,5v there. Installed also an new wire from the bulkhead to the VR.
The thing that I'm wondering about is that the VR sees the overcharging, but don't seem to do "anything". I can measure 15,5v from the key side but it doesn't seem to regulate it.

Any ideas what to do next?