cyl head valves

[deepdale]

I've taken me valves out with a view to just lapping them back in but have noticed that there is some rock in some more than others. I know there will be some but how much is too much and how do i check it.

With the valves held on the seat rocking the collet end there is very little if any movement. but if i lift the valve off its seat there is more on the head end. How much is the next question for valves/guides.