I cant recall the history of the recommission but do you perhaps have a non ballast type coil fitted on a ballast resistor wiring system or a ballasted coil wired directly?
The original OE coil if still working will be a million percent more reliable than any modern replacement, ditto for genuine New Old Stock.
Your outings with this vehicle and its capricious behaviour remind me of when I was travelling in New Zealand and was given a Nissan Prairie that had been converted for camping and had been off the road for a decade, the guy had converted it to carburettor fuelling from fuel injection using second hand parts and there was rust in the fuel lines etc, driving up the ridged ramp on the ferry to the South Island created such vibration that I knew exactly what would follow, sure enough within a few miles the progression circuit was lost and I had to keep driving on full throttle high revs until I could find somewhere to pull over.
I didn't have any choice, I rolled off the main road and coasted as far as I could, it was outside someones house and he came out while I was under the bonnet cursing myself for not having equipped myself with the right screwdriver for the jet, the owner came out and I expected him to give me a hard time but no, it was anything I can do to help you mate!
When I had got it running after explaining the problem he said "so its going to happen again then! keep the screwdriver, I will get another one!"
I had so many similar experiences with the Kiwis and I love each and every one of them, I also had a real attachment to the Nissan Prairie and sold it to an incoming traveller and posted the money to the guy who gave it to me, the ex of a girl I had a relationship with there, thats how decent Kiwis are! He even let me stay in his house, use his workshop and tools and spare parts to get the vehicle running again.
If the day comes that you have to part with that vehicle you will find it as hard as I did, I hope it will be to someone deserved.
Its funny how I appreciate the Skodas I have driven for the last 18 years for their reliability but that does not create the attachment that an unreliable challenge vehicle does!
Same colour as mine as well.