Is this unheard of for the particular ramp profile on the cam? eg does anyone else use this cam and can a comparison be drawn?

12 and 14 thou seems a little on the large side to me, but then I dont know CVH engines/the cam tolerances.

Are there possible oil starvation issues on the top end?

As a comparison my old rusty 16V Vauxhall which had a set of non hydraulic cams in was shimmed for 10 thou inlet and exhaust had. 6000 miles later, when inspected for sale, the shim gaps were still 10 thou. 500miles is taking the piss.

Can't help re the spring poundage, who specified it?