Sub- Contracting a 20k Job in Houston

I work for a large company and they are giving me large jobs. This one is about 20k. I plan to sub contract the entire job out. What is a general finders fee. What percentage should I pay myself. I plan to eventually have 2-3 sub contractors working on homes consistently. Should I take a % of the total amount of the bid which is created by the company and I have little say in or should I take a percentage after material cost.