Building a customised 1/4 scale patriot rocket
Frankly, the STM8S was a mission to get working.
You can choose between a very old toolchain, using the free cosmic compiler and stm8 IDE, or setting things up yourself with VS Code and SDCC.
Luckily for you reader, I now have a functional VS Code setup, earned through blood sweat and tears.
Check out the FC_dev branch for further details.
Openrocket
Setup is very simple, download from here. A really good intro to improving sim results is here.