Hi Hannes,
First of all, I can agree that having shorter baselines can help obtain a more reliable connection between the base and the rover. In the case of using an NTRIP service, this means connecting to closer mount points.
But, either receiving corrections from an NTRIP service or using your own base to stream corrections via LoRa radio, the solution and accuracy highly depends on the environmental conditions. Surveying in a forest or with buildings nearby and having limited satellite visibility will probably make it more challenging for the receivers to obtain a stable FIX solution and can affect the achievable baseline, too.
I’d also like to share our Support tip with several ideas and thoughts about the configuration with LoRa radio.
Please feel free to share any further experience!