Hi Jim, the floor that I replaced was in my old boat, a 29 Mk II. On that boat it was pretty straight foward, I took out all of the pieces and used them as a template to router cut the new ones. After the pieces were cut I flipped them upside down and routered the edges round so that they would fit easily into the fibreglass floor pan.
Are you sure that the floor on your 30 Mk I goes under the bulkheads and benches? I've seen this before on an early 80"s Hunter 34 but I didn't think C&C's were made that way.