[Roadsters] Valves leaking while cc'ing

[Daryl Smith]

Just got my head back from the machine shop and was cc'ing (measuring) the
combustion chambers.
Noticed a small amount of the fluid leaking out a couple of the ports, tells
me the valves aren't sealing quite properly.......

Took it back to the machine shop, and he tells me that happens sometimes and
to hit the valve on the spring side a few times with a rubber hammer and it
should seat properly......

I did as he suggested, and the leaking is less, but still there........

Is this common on a fresh rebuild?

If I put it on and run it, are the valves likely to "run in" and seal
properly?

Thanks