IF you get plans for a boat that are scale, cut & trace, and they are not large enough for you there is an option. Look in the yellow pages for printing companies in your town, or REPOGRAPHICS.... They make the blueprints for construction sites.
Decide how long or tall you want the boat to be. Find the plan piece that is the longest or tallest and tell the person the size you want. They will determine the % needed to make it right. Then the plans will be enlarged by that % each page.
So you know I had plans for a 48in. tunnel hull. It is now 73in. long. Bigest problem is finding an outboard motor that will fit that will not cost both arms and legg. Good luck.
Phil