Don,

An oil change has absolutely nothing to do with a valve adjustment.

Get .003, .005, .013 and .015 inch feeler gages and use them for go/nogo gages. .003 and .005 for intake and .013 and .015 for exhaust.

Hot and cold do not mean ambient temperature, they mean hot is running temperature and cold after engine has cooled to ambient temperature.

Don't expect miracules from a valve adjust. If engine starts easily when cold, probably none of the valves leak. The adjustment will prevent any of the valves from leaking in the future.

P E H