The calculations work out for lineal yards to get under the 150 lb limit. My box read 256yds, so for 44 in. wide 7.5oz glass:

256 * (44/36) * (7.5/16) = 147 lbs.

Plenty of lee-way for that cardboard core.

: There was an auction on Ebay almost a year ago in which about 20 rolls of 7.5
: oz. cloth sold for $72.00. Shipping was another $50.00. Each roll
: contained about 250 yards of cloth. I haven't measured it but I think they
: are linear yards. I bought a roll along with several others on this board.
: I don't think the seller has any more but I think I still have his e-mail
: address at home if you want to try to contact him.