About the valve cover bolt boss...don't worry about it! Grind it out! Years ago...in the early 90's I worked for a guy that did a lot of rounds rounders. They used 9:1 358, no porting...1" in from valve seat and 1" in from intake face. They had to use stock block, a factory head...the Chevys could use a bow tie...any cast manifold and a 650 Holley on alky. When I started they were dynoing right around 435 hp. I started doing the heads and when I left we were making 585-595hp!!! We were ALWAYS tech'd...they all thought we were cheating but the heads always passed! We had track champions at almost all the tracks and always had guys up front! Our stuff was fast!!!! Everybody wanted a CMS Racing Engines motor back then!
Back then it was taboo to touch the SSR and the closed chambers were thought to be the best because they could make compression. When the second gen bow tie heads came out they had a bathtub type chamber versus the first gens which were more of a semi-open design. I remember the first time I started laying back the SS and the chamber and everyone told me that you can't do that. I even saw a lot of Slawko stuff from the time and they never did either. I was told "look at them...they are the pros"..."you ruined those heads"...until the flow numbers went from the high 120's @ 10"....an SF-110 back then....to 155-158@ 10" and we made TONS of power....these days every one knows those areas can give the biggest gains but also the biggest heartaches....ask me how I know....
My point is that almost everyone of those heads had the boss ground out and I never thought twice about it!