if you do some squid hacking you can config it however you like... I did an example to exclude a certain site from being cached, but you could change other options too, like cache size.
My example,
logged on locally as root on the server
cd /etc/chroot-squid/etc
cp squid.conf-DEFAULT squid.conf-OLD (in case I screwed it!)
vi squid.conf-DEFAULT
added the following two lines with vi: (might have to read up, it's a pig to use)