Believe me I'm not one to try and convince the stunt community that silkspan is no longer available or that there is a shortage.
However, I do like making other aware that there are alternatives. The time I needed silkspan the only material available was from Brodak. I tried it and was very disappointed with the results. I've also tried Polyspan as well. With Polyspan, it is very strong but takes a considerable amount of dope to fill the material, then you have to deal with the "fuzzy's" if you sand through and the filling of the holes can be a pain. I've tried Monokote and I'm just not very good with it.
To cover a full-size stunt ship I would need four sheets of silkspan. From Sig's website a sheet of silkspan cost $2.90, that would be $11.60 plus $9.95 for shipping, my cost is $23.20.
When I bought my case of 12 rolls 18 months ago, I paid $26.00 and shipping was free. I'm sure the price has risen since then. That worked out to be $2.16 per roll. Each roll is 21" wide by 125 feet long (that's "feet" not inches). One large full-size stunt ship will use about 12 feet. One roll will cover roughly 10 full-size stunt ships. With 12 rolls I had more than I will ever need in my lifetime.
Purely from a cost standpoint you get more "bang for the buck" with the doctor's paper. Sure I could have sold the extra rolls and recup my cost, but I didn't.
Most important to me is that I can't tell the difference between the doctor's paper I use today and the silkspan that I used 40 years ago.
The other nice benefit to purchasing a box of 12 rolls --- it makes for a nice gift to give a roll to fellow modelers.
Dennis