I just recently rebuilt my engine and had a head job and I had the small holes issue for the oil and it did cause big problems on the highway especially abour 65. got pissed janked the head off and had a extra head gasket. cut the holes bigger with a metal hole punch. then put it bqack together WOW new engine more power and runs like the dickens. no problems.
Now to the ticking noise if the rebiult included new lifters as it should have they will tick for about 10 min untill the get built back up this is not a problem mine ticked for 15. then no problems.
since you just installed the head pull it back off and fix the head gasket. should be able to re use since you only ran it for a min or two. make it easy on your seld and leave the intake manifold and carb atttached to the head when you pull it can be done in about 3 hours and running again.
hope this helps