When I've tried to get a hand-back cancel they do not allow it here. Even at the Philatelic branch of the Post Office downtown they only allow it with their own special cancel, but that one doesn't have '
Canada Post' as part of it so doesn't look right to me.
Perhaps it's just me and the way I'm asking. Otherwise they all seem very friendly.
As for mailing stamps to one's self I think it is OK as it is going through the mails and serving it's purpose. I can ask for a rectangular POCON (usually used for money orders) hand stamp, that they do use to cancel parcels and mail. But if I just post the letter in a box or counter-receptacle at a post office it goes to the sortation plant and through the machines and gets a two or three line spray on ink jet cancel.
This is OK to me know. I do prefer circular cancels but there are none to be found close by. I could mail a bunch (reasonable amount) of letters in a larger envelope off to a post office somewhere, where I know they have a circular cancel and ask for that cancel. That is OK to do here. Just adds to the cost and you hope that the canceller cancels it the way you like, if you are picky that way.
We have a paper label that can be affixed (with tape????) to the mail that says Philatelic Hand Cancelled Mail / Manual Sort Mail , that will not go through the machines and preserve the original cancel.
I do send a lot of Picture Postage stamps I have created myself (requested to be printed) sometimes through the mails to myself as I am trying to leave behind on the sheet of stamps, true mint stamps. I find it hard to cut around stamps too closely.
It is fun to do this as I can play with where the stamps are placed exactly on the envelope so I can try to get the date or postal code or 'canadapost.ca' part of the ink jet cancels on the stamp in a readable area. I have noticed some collectors paying more for these types of cancels already. Not a lot, not everyone, but then, not everyone wants nice SOTN CDS cancels to start with anyway.
But some do prefer just a hint of a cancel on a stamp, leaving most of the design free, and this can't be achieved by placing the stamp in the exact upper right-hand corner. That will get a well and truly cancelled stamp usually. Just move it back a bit to the left or down a touch and it is still OK and serves the purpose and will be machine cancelled but not look like the printer has had a field day on it. Personal preferences rule here also.
The fine art of cancelling a stamp I think of it as. Nothing philatelic about it. Plain asthetics, what is pleasing to the eye.