UPDATE
decided to flick third party services for now, the cost is too high for what i want to do (and for what i can charge people for)
im using a Virtual Machine running Linux, with Grafana and Influx setup on that.
on the remote computers / servers, i am running telegraf and that is sending metrics to the WAN of where i am hosting the Linux Grafana box.
I wish Dataplicity's Wormhole would have allowed me to view the Pi's Grafana Website ANYWHERE, id gladly pay them for that. But it dodnt work, I could not change the reverse proxy settings to allow it to show Grafana internal dashboard site, instead of the Welcome to Dataplicity page on your device:yay.
oh well. Im keeping one pi alive on Dataplicity because the remote access to the pi from there IS USEFUL....not at $2 per month just to reboot it, but i might figure it out later.
and no, not offline database, im using Influxdb on the same VM as Grafana. host OS is ubuntu.

Couple of pi 3's, a pi 2 and an assortment of hardware.
your move brain.....your move