So, how small is that cows knee, Sonny? IMHO, people make 'em too short to work right. The only original I have seen, and those in photos are pretty long.
In my experience, and based on originals, a good cows knee should reach down the wrist, to at least the point of the comb, and down the forearm for at least a foot in front of the lock. IMHO, longer is better though. Nor do they need to be tied in place when still hunting, or stand hunting.
A cows knee can be removed as easily as the 3/4 length cover offered by Curt Lyles.
IMHO, the only real difference in a historically correct cows knee and the one offered by Lyle, is the cows knee is fitted to the contours of the gun, where the 3/4 cover is not. The cows knee is also somewhat shorter and doesn't cover the muzzle as the 3/4 cover does.
Either option will work, if properly made and applied. And neither will get you a ticket from the "authenticity police."
As for water proofing, linseed oil, mixed with oil based artists paints ,and thinned with mineral spirits work well, but seems to take forever to dry.
The pigment seems to help fill the voids in the fabric, while the linseed oil binds the pigment to the fabric, in addition to soaking into the threads.
Re boiled linseed oil blended with hot beeswax, applied hot, will also provide good water proofing.
I suggest washing your ticking in HOT water, several times to shrink and tighten the weave prior to applying any waterproofing. A tighter weave will help with water proofing.
God bless,
J.D.
