Good evening,
I am attaching a link to the GIA, German Imperial Army, and one uniform plate as a guide. From your 2nd photo I would use the right arm to decide on the cuff colours. It is much clearer than the left which is faded out.
When looking at the plate the parts are as follows;
top collar
main colour tunic, buttons down right
center top shoulder board with regtl number
next down sleeve with cuff at bottom
bottom left rear vent and buttons on tunic
center band belt and buckle
bottom right trousers
trousers and tunic also show colour of piping
https://kaisersbunker.com/gtp/On main page sect infantry and below is a list of regts. 2nd column gives a description of the uniform parts and colours.
I will look through as well but it could take time.
John915
Added; Your man has brandenburg cuffs so ignore any with Swedish cuffs. He also has white piping.