Front driveshaft length?

I now have my dana 30 in, the one with the disk brakes. The question I have is about the length of the driveshaft with the vehicle just setting there. I measured my rear shaft for the slip in the yoke when it was all the way compressed versus where it sits when just sitting under its own weight, there seems to be about 3/4" of play to compress it all the way compared to just sitting there all hooked up. If I use this to figure out how long to make my front shaft (remember I had a v6 with the small yokes and the dana 30 has large yokes, so I'm using the driveshaf that was originally hooked to the dana 30) I measured the distance to the centers of my front yoke to the axle yoke and got 24", can Joe or Lynn or anybody else with this setup confirm this length, and does my thinking about the extra play sound about right, I know I need a little but not sure how much and the driveshaft only has about 2 1/2" total.

 

FWIW Mike
a stock 72-73 front shaft (CJ5, D30 and D20) is showing an OAL of 27.73"
this is collapsed, center to center of the u-joint caps in the yokes
FWIW a V6 shaft is showing on OAL of 20.81" to 21.75" measured the same way as above
I would say, take your static measurment as it sits, allowing for at least 1" (minimum)slip either way in the splines
my 0.2

 

Think Tom Woods has a good chart on his page. At least a detailed way of telling you what you need.