That's excellent. I might try and work out something similar for a beetle tank as someone recently gave me one for my buggy that needs rewinding.
I had one of those too - can't remember but I think it was on a '66? It worked on a cable I think, like a bicycle brake cable.
I take all that messing about calibrating on Samba with a pinch of salt... These guys mess with the sender through their made access panel. That's all they do on that thread, but... The wire from the gauge leaves the loom and is routed via the wheel tub, probably to maintain the firewall. Just inside the area accessed by the paint tin lid there is connector - Aha! That connector has sat there corroding a little for 40+ years. I guess damp tracks up the wire. You can see where I'm going with this. I unplugged it and plugged it in a few times to clean it up a bit, satisfied myself that the connectors were tight, fitted my sensor out of the box and my gauge reads exactly full when it's full. If one's gauge is under reading this is another place to look for that added resistance. Sadly you'd be lucky to even get a photo of this connector through the paint tin lid hole and it's quite close to where it emerges from the tub... Cleaning it up with one hand blind through the lid hole is a bit of an ask...impossible I'd wager... so it's an engine, firewall and maybe even tank out job to get two hands on the little sucker. I honestly wouldn't mess with the calibration of the gauge or sender until you know you have 5.3(??)v and that connection isn't adding resistance screwing the whole thing up and causing ones gauge to under read.
Mine was 65. Most amusing setup but mine worked great. I didn't look hard at it but I can imagine calibrating it by adjusting the cable would be a doddle!
