Warping with Wool

I’ve never woven with a wool warp before (always used cotton). I have some Donegal Studios tweed wool yarn that I would like to use as warp to make a 90” long scarf, 8 epi, using hopsack weave. The wool yarn has a lot of stretch. I’d appreciate any tips regarding stretch, take-up and shrinkage. I am concerned that I will under or over estimate how many inches to weave under tension, to produce a 90” scarf after the piece is removed from the loom and wet finished.