Cylinder head surface machining(home remedy)

[dom14]

These are the photos of my bench machining setup & the job I partially finished on the RB30 head.

Can you guys have a look at the photos and advise me whether I need to machine it further?

I'm particularly concerned about the pitted/porous surface around few of the water jacket lines(see photos).

I used 320 grit wet sandpaper with a bit of WD40 sprayed on it to machine the cylinder head surface.