Spring in parts of canada is quite bad. I am a flight instructor in Ontario, and i know i have had great months of flying hour wise in February and january in the past. But during the transition of the seasons from March-May, it can be very challenging with freezing rain, low clould etc.
Ive been to Cornwall aviation, i went in November to do their fast paced program, most people who were there when i caught up with them after they finished had taken 4-6 weeks, ive spoken to those who went in summer and they got in and out in 3 weeks.
All flight schools will accomadate an expedited time scale as long as your paying. i have done these before and generally what will happen is my CFI will come to me and say "this is Billy, billy wants to get his license by X" and then off we get to work. I do work for one of the large schools, but i dont understand the "rigid in their Sylabus" comment, we train as per the CAR's, and i know the other big schools do also. Ive also worked in a small school, and it was the same there.
You mentioned you have 325 hrs, for the CPL to be issued youl still have to hit the expeirence requirements like, 50 X country PIC, 100 hrs PIC, 20 hours instrument post PPL etc for the issuance of the license.
The next comment i am going to make is a general comment based on my expeirence as a flight instructor doing these conversions, sometimes its not as straight forward as the canidate expects. Often higher hour students expect to breeze through the course but they may not in fact be able to meet the standard and will need more work to get there.
Anyhow, all i can say is canada is an amazing place to fly. In fact if you get good breaks in the winter weather in canada its the best time of year to fly. PM me if you want me to send you specific details on my school or want information on other schools as i have colleagues or ex students scattered around most of them.
p.s. harvs air has amazing online school content to prepare for the CPL, INRAT etc.
In canada, the aviation forum of choice is avcanada.ca