Size volume required for iPrint

Am setting up a three-node cluster with NW 6, and, wanted to put
iPrint on
the cluster. We have about 225 printers in 25 different models, and
have
1300 people who print to them. I'm not sure on volume size (I assume
it
must contain the drivers, "queues", and support structures) but was
thinking
of 20 GB. I'm also assuming that I want a separate volume...

Does this sound reasonable, or too large/small?

TIA!