apt-cacher as package rollback buffer

[freeman <freeman@worldwidehtml.com>]

I installed apt-cacher because I wanted a way to reliably roll back one
version of a package in testing.  This way, if a new version is buggy, the
way the recent xserver-xorg/mesa was for me, and I let it slip by
apt-listbugs, I may possibly choose the old version from apt-cacher rather
than nearly total my system messing with it, as I did.

It will be necessary for me to manually run the cleaning script on occasion
to avoid random deletion of old versions.  For this reason I first chose
apt-proxy.  It has a nice config allowing specification of an exact integer
for the number or version to retain for each release.  Couldn't ask for more
than that.

However, I got python errors and the hour was late.

Has anyone else had success with such a plan?

Is pinning really necessary or can I get by with aptitude and my apt.conf
file:

APT::Default-Release "testing";

?

I did read the page on approx, pinning, repos and more by one of our prominent
list subscribers.

TIA!

-- 
Kind Regards,
Freeman