Compression gauge fittings

[philr54]

What type of compression fitting would be most useful for these scooters (screw-in or rubber cone)? Or does it matter?
I understand the basics of compression testing but have never actually done it.
My thinking is 50 miles a day carrying 280 lbs at 45-50 mph would be hard on these little gy6 engines and I haven't found any reasonable estimates on life expectancy for a gy6. If the compression starts to decline, I can re-build/replace before we have a catastrophic failure.

[Rebel]

I have a personal preference to the screw in type. It just feels better to me than pushing a rubber end into the spark plug hole, I feel like it makes a better seal and a more accurate reading. Probably in reality it makes little to no difference.

[jmkjr72]

i like the screw in type also plus you can get adapters for just about any type spark plug with the screw in

[workdog]

I use screw ins.

[philr54]

Thanks All,