Agree Dan - but for the vast majority of builders gaining engine efficiency in cruise would override building fire breathing “time to climb” RVs.
For those running such high compression engines I suggest careful thought be given to imposing POH limits on engine MP, retard timing, or both. My “around the world” Lancair IV neighbor restricts MP on takeoff for his 10-1 Continental 550 engine running dual electronic ignitions (a couple of degrees retarded on base timing and ~9 degrees max advance). The timing is at base for takeoff. He needs both the high compression and timing advance to gain fuel economy (38 hours on a tank of gas). The restricted take off MP and selected base timing (no advance for takeoff) helps mitigate detonation risk. He just rolled 2000 hours on this engine - only one jug had to be replaced.
Carl