where`s pittsburg racer when we need him ??
I`d unshroud the valves out to the edge of the head gasket , (cyl. bore) , ''smoothly'' , mindfull of compression loss ...
I would do the same. Lay it’s out with blueing and a properly secured head gasket size that you will be running and scribe a line. Then gently lay it back with a couple old valves protecting the valve seats. You do NOT have to push it up to the scribed line. Leave yourself a safety area. Excuse the roughness of this picture but this is the area I would lay back