The milk jug washer is not only meant to protect the secondary mirror stalk from the adjustment screws otherwise a metallic washer would have been good enough.
The main benefit of the milk jug washer is to provide little elasticity to make fine adjustments -- something a hard object like a metallic washer or even a hard plastic will not provide. That is why I suggest using 1 or 2 washers to provide different levels of elasticity.
The elasticity of the milk jug washer seems about to be the right amount.
In addition, it is easy to install. If the scope owner does not want to remove the secondary mirror then he/she can make a radial cut and slide the washer in as I have shown in post # 8 in this thread.
Yes, this is it and it works very well. I used black Kydex from Scopestuff, and have 2 of them stacked between the seconday holder and the screws.
Hi Steve, I did not know Scopestuff carries them. Did you mean Opticsmart?
Here's a link: