Look for the best examples on other cars. Talk to the owners then go to the venders. Most likely you'll have to buy the screws from a place like Restoration Specialties Supply Inc. So go back to the owners of similar cars and see if they will help. Sometimes there are some oddball screws such #6 oval head on #8 sheet metal screw.

Parts and shop book may help too. Probably won't give you all the details but may show how many and how many different types, whether its a self tapping or there is a retaining clip.