I’ve had several sets come through my shop in the last 18 months or so.

From strictly a “functionality” standpoint, none of the ones I’ve had here in the last few years had anything wrong with them to the point where they would have caused any “problems”.
Sure, the valve job and the way the seats transition into the bowls leaves some flow on the table....... but that wont cause any issues that would leave you on the side of the road.

I can’t think of a single set of aluminum Chinese heads I’ve prepped, for any engine platform, that had the guide clearance too tight.
If anything, they’re generally on the loose side.
Yes...... they probably should be checked....... but tight guides wouldn’t be something that typically needed correcting on these heads.

Btw, I haven’t looked at their website in a while....... but the advertised flow #’s at one point were pure fiction.

They are typically in the 260/185@.600 range ootb.