In a noisy engine bay it might be worth using the stethoscope/long screwdriver method to ensure that the clearances sound uniform across all cylinders..
I remember watching a mechanic setting clearences with the engine running at tick over... I guess he went through more feeler gauges than most.
I guess finding the rocker with the widest clearance and turning the engine a tad with the spanner to ensure it is at it`s max clearance then checking and adjusting as necessary... With that one done look for the next rocker with widest clearance and repeat the process and on and on and on. If you have the firing order then I guess it will not take too long to work things out..?
Best of luck K
