The Spark needs at least 10 satilites to get a Home Point lock. More is better.
And you should receive more satilites as you rise up higher in the sky and capture more signals,
but ONLY after a Home Point has been established.
The are three phases of the Spark warm up, Atti-mode, GPS, and GPS Ready to go (Home Point).
If the Spark is satisfied with a Home Point, so am I.
I'd set the UAV Forecast app to 10 satilites and see if that works for you. You can set other parameters too to your liking such as wind speeds at 200 feet verses the ground.
Happy flying.