Here are Real Life power settings for Merlin III and Merlin XII during BOB era:
Merlin III with CSP at 87 Octan fuel:
Max take off - +6 1/4 at 3000 RPM
Climbing (1/2 hour limit) - +6 1/4 at 2600 RPM
Continous cruising- +4 1/2 at 2600 RPM
All-out level flight (5 minutes limit) - +6 1/4 at 3000 RPM
Merlin III at 100 Octan :
Max take off - +6 1/4 at 3000 RPM
Climbing (1/2 hour)- +6 1/4 at 2850 RPM ( below 20 000 ft)
-3000 RPM (above 20 000 ft)
All-out level flight ( 5 minutes)- +6 1/4 at 3000 RPM ( 5 minutes)
Emergency power (5 minutes)- +12 lbs at 3000 RPM ( 5 minutes)
Merlin XII at 100 Octan
Max take off - +12 at 3000 RPM
(probably emergency 5-minutes also)
Climbing (1/2 hour limit) - +9 at 2850 RPM
Continous cruising- +7 at 2650 RPM
All-out level flight (5 minutes limit)- +9 at 3000 RPM
I really hope and want to see such power settings in CLOD RAF fighters
But probably it would be miracle if we see it