Passing the Thinger credentials to an ESP8266 executable without recompiling

I have a rather large programm for the ESP8266 that needs about 20 parameters that I currently adjust before compiling.
I would love to be able to distribute a common runtime loaded with without asking the user to compile and get all the libraries, which is rather a touchy job.

The WiFi data are given using Smartconfig, because it does not need additional libraries.
(I am close to the max Program memory)

My precompiled program could read all needed parameters from a Thinger’s device property during Setup, but I need to pass at least the credentials for Thinger.

Doing it over a Web-interface just needs too much resources.
Does anyone know how to pass these three parameters using

Thank you for any clue…