How often do you run the overhead on a 24V, and how hard is it...

 

i usually adjust them every 200,000 miles or sooner if i have a gasket leak, it is easey the hardest part is the ones under the dash, i have used a system for the last 40 years where i do not use timing marks , for first time i would do a search and print out the sequence and mark them with a felt marker as you adjust, it is 0.010 and 0.020 the same as 12v the first time will take about an hour

 

Just did mine at around 90.000 miles and they wern't out at all, but its a good piece of mind.