I run desktop (not mobile) Firefox with an in-memory cache only. My opinion is that on-disk cache with several days (or weeks) old content is almost entirely useless, and that the most beneficial cache use is what you fetch/reuse through a single day of running browser.

Here's how you can "make the switch":

First of all, clear your disk cache entirely. Then, head into "about:config" and change accordingly:

  browser.cache.disk.enable -> false
  browser.cache.disk.smart_size.enabled -> false
  browser.cache.disk_cache_ssl -> false
  browser.cache.offline.enable -> false
  browser.cache.memory.enable -> true
  browser.cache.memory.capacity -> 512000
  browser.privatebrowsing.forceMediaMemoryCache -> true

The number 512000 is in kilobytes. Adjust to preference. Firefox will still do some caching to disk, but these settings stop the most pressing disk writes. You may confirm the change by visiting "about:cache".

I use:

    git init --bare $HOME/.myconf
    alias config='/usr/bin/git --git-dir=$HOME/.myconf/ --work-tree=$HOME'
    config config status.showUntrackedFiles no

where my ~/.myconf directory is a git bare repository. Then any file within the home folder can be versioned with normal commands like:

    config status
    config add .vimrc
    config commit -m "Add vimrc"
    config add .config/redshift.conf
    config commit -m "Add redshift config"
    config push

And so one…

No extra tooling, no symlinks, files are tracked on a version control system, you can use different branches for different computers, you can replicate you configuration easily on new installation.