I've listed 25 different tarp shelter designs to help you get started. Each configuration has its pros and cons and there isn't really a perfect design for all occasions. You'll have to chose the right one depending on your situation.
How to Fit Yourself on a Mountain Bike. This portion of article is a bit convoluted; Bikes need to be sized by Stand-Over-Height, and personal performance expectations/needs, NOT this method. In my humble multi-decadel professional opinion.