I've updated the code on github to report every event over MQTT. It also reports the CPM and the time passed since the previous event as (CPM,dt). It uses the uMQTT micropython library, which is very straightforward to use. If you have any suggestions for extra info in the messages, leave a comment below.
In addition I added a micropython firmware in the FILES section. (version 1.8.3, with 10kHz PWM support)
The software side of the geiger counter runs quite solid now, I will start focusing on the hardware again. Next step will be moving the circuit to a PCB (I'm thinking a shield for the WeMos, either using the WeMos ProtoShield or go for a custom oshpark/dirtyPCB thing)
Also I'm still searching for a good source to calibrate the HV (In holland it rains every day, except when you want it to.)