My KC is powered by a Titan SE set for 117,000 RPM maximum. It is overpowered at this RPM setting. A P-120 is plenty in this airframe here at sea level (Central Florida).

My flight timer is set for 9 minutes, and I try to land before it expires. The remaining fuel level is usually the near the aluminum adapters in the mains, seldom going below the plywood tank retainer.
I feel that it is smart to allow an amount of reserve fuel for a couple of missed approaches or slpw orbiting in case the runway is not available for a minute or two.

I usually throttle back to about 75% power after take off and only use full power for verticals.

A P-120 would be more fuel efficient.