No one mentioned this so I will.

I believe that the OS LA 40 is way undersized for this plane. The Sr. Falcon is a large aircraft, and getting that size plane off the ground in grass is a challenge. I would opt for at least an OS 46 AX or the new OS 55 AX engine and prop it accordingly. Especially if you are flying in a limited area as you say you are.

I know that the OS 40 LA may be the recommended power for that plane, but you obviously have seen that it lacks somewhat in the power band using standard props, and getting it up to 16,000 RPM to get into it's power band is not practical... especially if you want to keep that engine running for longer than a few months.