I recently bought a Kampfe Star razor that did not come with the old wedge blades. As a result, loading a Gem blade in it to shave with required a little more care than my other SE razors. I attempted to shim it using the spine of a discarded blade, but it was still not quite the solution. I just happened on TSR which is the UK version of B&B and found that they are heavier into the older SE razors than we are and someone designed a 3D printable wedge specifically to mount a Gem blade in an older razor that required a wedge blade.
The link to the file is: http://ift.tt/2akwyl8
a pic of what it looks like
It will not replace the shim for razors that take the regular Gem blades. This is only for the razors that require a wedge blade. Have not tried it myself just yet but it does look hopeful.
Gem blade wedge