How to use a relative path from web.config runtime linkedConfiguration

Question

I am attempting to use a relative path with the <linkedConfiguration> element. I am able to specify a full path to my runtime.config and it will load it fine but I would like to set this relative to the AppBase which is displayed in the fusion log. I have tried the following.

<linkedConfiguration href="file:runtime.config"/>
<linkedConfiguration href="file://./runtime.config"/>
<linkedConfiguration href="runtime.config"/>
<linkedConfiguration href="./runtime.config"/>
<linkedConfiguration href="~/runtime.config"/>

I also found this answer but unfortunately it did not work for me. This is the only path that has worked for me so far.

<linkedConfiguration href="file://C:/Perforce/{product}/Branches/Working26/UI/Web/{website}/runtime.config"/>

The {} are for information I redacted from the URL.

Here is where I put the <linkedConfiguration> in my web.config.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  ...
  <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
     <linkedConfiguration href="file://C:/Perforce/{product}/Branches/Working26/UI/Web/{website}/runtime.config"/>
  </assemblyBinding>
</configuration>

and here is the runtime.config.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <runtime>
    ...
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Lumberjack" culture="neutral" publicKeyToken="bef447dd453f4f84" />
        <bindingRedirect oldVersion="0.0.0.0-12.400.0.0" newVersion="12.400.0.0" />
      </dependentAssembly>
    </assemblyBinding>
    ...
  </runtime>
<configuration>