I'm trying to customize my own trenchcoat...I'm 5'6"-5'7", and typically wear smalls or mediums. Looking to design a trenchcoat that comes down to mid-calf. I want to have the coat made out of fish leather, but I'm not sure how much I need to order. I'm thinking maybe 50sqft, just to be safe? I'm new to creating an article of clothing from scratch, so would appreciate input...for reference, this is the design I'm going to try and work off of.