On the ex/in stroke the exhaust valve closes after TDC and the intake opens before TDC so there won't be much pressure to feel at the plug hole. But on the comp/ign stroke both valves are closed at TDC so the pressure will blow your finger out of the hole.
And would suggest having someone "bump" the starter with the key or use a remote starter switch. As it starts to come up you'll fell the compression as mentioned. keep bumping it while watching for the timing mark as it approaches TDC while bumping.
if you go too far, you will have to rotate the crank almost twice to get back to to the compression stroke.
