Sorry, I do not see any info in the link, so I only can tell, how I would have done it.
First config, to start with, to keep it simple:
Squid to be put into one dedicated PC with eth0 and eth1. eth0: to your LAN, eth1: to the MT-box.
Also to run DHCP-/SNTP/(caching-)DNS-server in the squid-box, because it would be default gateway for the LAN, anyway.
squid-box needs routing, of course, and has MT on eth1: as default gateway.
All client-PCs in the LAN then need to have the squid-box as a HTTP(S)-proxy to be configured in the browser, using a proxy.pac, for example.
Next step would be a transparent setup for squid, which means, to get rid of the proxy.pac; although more convenient for the users, setup is more complicated and failure-prone, so only to try after the simple approach is up and running.
You will definitely have a positive effect regarding response times; depending on your users and the size of the caching-disks, you might expect a hit-rate of 30% to 50% or even more.
Very important: The setup of the filesystem for the caching disks has a huge impact on performance. I would recommend a "degenerated" ext4 (no journal etc.)
However, for more squid-specific issues, use
http://squid-web-proxy-cache.1019090.n4.nabble.com/
There are the developers to be found. And me, too