binding machine

i hope this is an appropriate newsgroup for this question. i am a composer
and am looking to self-publish my scores--most of which are on 11x17 paper.

i realize that most personal binding machines will only bind an 11 inch
edge--but some have the punching slot enclosed so that only 11" paper will
fit. Others have open lips so that you can slide larger paper through and
bind just the middle (or bottom) 11 inches of a 17" edge. I am looking for
the latter, so that I can bind large scores.

Unfortunately, this detail isn't usually mentioned in web-based shopping,
and the office supply stores I've visited only have 2-3 binding machines on
hand, none of which have open lips. I don't want to order a machine
blindly..

Do any of YOU happen to have experience with binding machines that will
allow me to do this? Brand/model names would be appreciated--as specific as
possible, so that I can order the correct one online.

Ideally, I'm looking for coil binding, but plastic combs will probably have
to do--unless there are inexpensive coil binding machines.

Thanks,
chris.