No matter how much I look at it, review and study, I came to the conclusion that the Barometer works well with SPIRIT and only with SPIRIT, and with the GeoLink there must be a communication problem between SPIRIT Barometer and GeoLink, this shows how capricious is the Electronics.
Therefore I recommend for users who have the GeoLink mounted, that the height data come directly from the GeoLink GPS, I am sure it will solve this, I will explain why, I suspect this, you have to take into account that an RC Helicopter does many height changes in the maneuvers in very short time lap, it is not like an RC Airplane,
so since there are so many height changes in a very short time, the GeoLink unit does not have time to calculate the data that comes from the SPIRIT Barometer.
I don't know if you have with Drones, I also have and fly Drones from more than 30 years ago, take a DJI FPV
(it is comparable with a Heli due to its high speed) and see how well the data that comes from GPS works, Height, Speed, Home Point, Direction all in Real time .
I think that on the part of the User Software it can be solved easily, since the GeoLink can be set to automatic self-detecting. This means that when the software connects it to the PC, it detects if the user has only the SPIRIT, or the SPIRIT with the GeoLink, to give it Data directly priority in case the GeoLink is installed,
and follow the data is taken from it. Hopes mi idea helps and makes it easier ,and more effective.