This took about 1.5 hours today to build. I suck at soldering or it probably would have been faster. For influxdb and Grafana, I simply followed the instructions on the respective websites.
I'm thinking I might add some calibration code to the ESP code just to fine tune things a bit, but for now, everything is working.
The Arduino OTA stuff for the ESPs is really great. Makes modifying and testing ESP code so easy!!!