so, the pcb's have been produced and are being assembled, though i don't know if i'll resume this exact project, as things happened.
like my screen broke during transportation (no spare screen as of now)
batteries arrived, but are too big to fit in the enclosure (ebay seller gave wrong dimensions)
and the high battery usage of course
i can try to optimize the battery usage more, ut that would require me to get a custom pcb for the screen, which will add alot to the costs for me as well, as i just don't have the right experience with pcb design.
note this doesn't mean i will leave the project as it is, i will most probably change the design quite a bit in the far future
(like using a TEENSY 3.1 based system and a little bit bigger OLED (160*128px) or go for a rpi based system)
ideas or suggestions on what to do are welcome of course :)