The rubber band shim

[riverrun]

The difference it makes for me is that without a shim I can't shave with the head flat on my face, with a shim I can.
Flat on the face seems a natural angle for me when using an SE.
This is based on my British made 1912.

 

[Rohleder]

To quote the instruction leaflet: "In order to obtain the best results do not hold the razor flat against the face, or at right angles to the face."

That said, I do agree it does seem to provide a better shave with the cap flat to skin... It gives me a ton of irritation if I use it any other way (with the modern GEM blades.)

 

[riverrun]

A length of bicycle inner tube arrived today, curtesy of @Vanvanlife (Thank you!)
It works really well as a rubber shim. Excellent. I had a really great shave with my 1912 today...
The tube was 27x1 1/4"

 

[Scotshave]

Great help @riverrun and everyone.

The somewhat crappy image shows a Gem with 2 Loom bands, one on top of the other (sort of). It certainly seems to reduce blade movement. The acid test will be a forthcoming SOTD.