Lots of questions
Small shower - Conserve water
Small galley - safer, you can wedge your self in.
Guns - don't even ask (do a search in the forums)
Size of boat - quality matters more than size.
I would suggest sailing on several different styles of boats before buying or building.
I sense you have not sailed much - get some training and experience.
ISPA Yachtmaster Offshore Instructor Evaluator
Sail Canada Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
ASA 201, 203, 204, 205, 206, 214
As I sail, I praise God, and care not. (Luke Foxe)