Measuring for a new driveshaft - does this make sense?

[RedRider]

Just finished a lwb to swb conversion and I'm looking to replace my two piece driveshaft with a one piece. I need a measurement for the driveline shop.

A couple questions for the drive shaft pros here:

To get the best measurement, I was hoping to measure from u-joint to u-joint. I pulled the slip yolk off the old shaft and pressed it all the way into the transmission. Then I slid a rigid piece of cardboard through the middle of front yolk:



Moving back to the rear, I made a measurement from the base where the u-joint rides (bottom of the laser measure):



Three measurements from three spots on the cardboard were all the same; about 60 inches:



Does this approach makes sense? Is there a better way to measure what I need?

Second question, how does this measurement compare to those running a 1-piece drive shaft? This is a 1970 C-10 w/ a 350 and 350 tranny. Also, what diameter shaft should I expect?