In reply to 914Driver:
Agreed. Your methodology is much more important than the numbers.
Until you drop a bridge on someones head. But that is why 3 people have to sign drawings. It is supposed to be triple checked.
I have always been given this. 1. Facts given. 2. What is known 3. Assumptions
Verify by checking units. Always check the units, did I mention check your units. Very good safety net.