Taking it to the engineer won't work for the simple fact that there will be several engineers and (professionals) from multiple agencies and companies reviewing our findings.  Using centerline of pipe wont be effective.  Pipe is buried and there is approximately 2000' to inspect.  We've set-up various dial indicators, this would work but is very time consuming.  Cam gage is the tool of choice, problem here is that I can't flash a picture to document to interested parties.  My current idea is to use a dual height gage -digital- and measure three points in between, -both sides of weld and reinforcement-.
thanks for everyone's input, if ya got more ideas keep'em comin!!!