I'd like to answer your question regarding the fact that the spot lamp can emit light outside of the lamp-post although it's inside. Instead of changing the "Clip Start" you should go and play with the lamp "Radius". If the radius is larger than the walls that are containing the lamp, then it will shine outside.
Oh yes, of course shinsaku , that makes so much sense!
Thanks a lot Yves for pointing that out 👍🏻
