Proper settings for 'Bandwidth' parameters

["admin" <admin@xxxxxxxxx>]

How should one "tune" a tor node using the Bandwidth settings?
What do BandwidthRate and BandwidthBurst stand for? (Exactly)

As an example: A cable connection has a 256 Kbps up-rate and a
3 Mbps down-rate. This obviously limits the in/out-rate of an
or tunnel to 256 bps. In order not to saturate the up rate of
the local users how should the parameters be set? (note the
dif between the b(its)ps rates and the B(ytes)ps rates used in
tor).

I know the tor system itself does some sort of load balancing
but it would be good to know what these things mean not to
set them up to an overly restrictive setting.