About the simplest/fastest boat to get into the water I would say is the Vac-u-tug. http://vac-u-boat.com
The gentleman who owns the company came to our last regatta to show off his wares, great guy-could talk to him for hours, there is a picture page on his site. They are a simple build and go together fast so you don't get discouraged. The instructions are well written. You can add more detail as you see fit.
Regarding the Sterling BB, the kit is set up for a single screw drive. I have seen an article somewhere on converting it to a 3 screw just like the original. For the life of me I can't remember where I saw it but I know it is out there.