I don't know Al you seem to have different opinion on front disc brakes than me, the only time my Norton front disc brake let me down was when they were 35 years old and worn out, a full front brake upgrade with a Grimica system fixed that as well my new 2013 Thruxton had a single front Nissin brake system worked great as well and my 2016 Thruxton has dual Nissin front disc system and ABS, both my Thruxtons have good braking even at high speed, but riding on the road for over 50 years and I always ride my bikes hard I learned to slow my bikes down without using my brakes before I go into corner and then powering through the corners up in the twisties, very rarely I use my brakes when out riding except for coming to full stops of course or seeing a speed camera van up front of me lol, using my engine braking to slow me down as well, my Norton front upgraded brakes work as good as my modern Triumph front brakes.
Riding with 50 year old brake system of course you are going to have problems with your brakes and what you have told us all Al your front brakes are bitsa, a bit off this and a bit off that, modern new braking systems work so much better than days gone by and there are many great brake systems around, Nissin, Grimica and Brembo have been around in the racing game for a very long time and it's how deep your pockets are to get the best disc brake system for your needs, you can go cheap but is your life worth it.
When my stock Norton disc let me down badly over 12 years ago, while recovering from the fractured left arm and broken thumb from the accident was when I upgraded the whole front brake with the Grimica system, was one of the best upgrades I done and at the time cost under $600 from RGM, my accident could have been worst, don't trust old worn brakes even rebuilding/replacing parts over the years.
Ashley