Coo, back again.
This topic crops up every year or so.
I run single cable, have done since 70's.
Only time I've ever had a problem was on 1967 CD175 when throttle cable froze (it was a bit chilly out

)
That was about 1974 or 75.
I've since done unknown amount of miles on two wheels (at least 220,000+ miles on my bikes and at around double that on other peoples (I was service tech/foreman/service manager in Suzuki/Yamaha/Honda/BMW dealers for years)
If you lube the cables, check carbs, service regularly, shouldn't have any problems. (I don't)
Main issues I've seen on other peoples bikes, frequent washing, pressure washing, high pressure airlines for drying and a fear of dirty bike so parts don't get lubed.
Looks good but every bearing is either seized or rough and cables are almost impossible to move or 'heavy' (just because they are graphited nylon liner doesn't mean you shouldn't lube them)