Thank you for your interest on Thinger.io plugins. this approach is very new in our platform and, at the moment there is not much information about it.
Actually, the plugins of the platform are not compatible with the Maker Server. The docker system is only supported by the new on-demand server instance, although you can deploy a nodeRED server and a Thinger.io Maker Server on your host and connect them via REST API in the traditional way.
The good news is that the price of the on-demand instance has been reduced from 200€ to 30€ including 1 plugin license. Maybe you can find a way to work with it.
If you find this interesting write to info@thinger.io and we will give you more details of how to purchase an on-demand instance with early-bird adopter discount this month.