A chat with boys at ATC indicate that it is not quite that simple and the Designated Airspace Handbook must also be referenced.
Lets face it ....this is a problem that does not concern many of our fixed wing counterparts.....they are rarely looking for the lowest useable altitude....and for the operation I am involved with the lowest useable altitude varies by 1000' whether we are in controlled or uncontrolled airspace off airways.
Here is a link......
http://ats.nrcan.gc.ca/english/ATS_dah_e.html
Jez
I'll take that into consideration. Thanx