I strongly suggest applying outland.
Here's the list of forms for Family Class spousal category outland on CIC's own website:
http://www.cic.gc.ca/english/information/applications/fc.asp#sponsor. As you can see, the Part 1 forms are for Sponsorship. That corresponds to the step 1 for processing your application, which is the sponsorship approval done at Case Processing Centre-Mississauga before they transfer the PR portion of your application to the visa office, Buffalo (you mail everything to CPCM though- you don't wait until they approve the sponsor to continue). Part 2 in that list is everything the Principal Applicant fills out. For Part 3 in that list, you need the region specific form for the U.S. -
http://www.cic.gc.ca/english/pdf/kits/guides/3910e.pdf.
Also look over the checklist in particular:
http://www.cic.gc.ca/english/pdf/kits/forms/IMM5491E.PDFYou are right to be concerned about "messing something up".......it really pays to be thorough and attentive to detail here because there is a lot of stuff that goes into this application and this process in general. And unfortunately, even those of us who have completely dotted our i's and crossed our t's have run into some hickups with CIC, particularly those pesky Buffalonians, but that's another story.
The medical and the FBI cert need to be dated as close as possible to the date you show up at the post office and put that thing in the mail. The reason: the FBI cert expires 3 months after the date on it so CPCM needs to have it within that time; as for the medicals, they expire 1 year after you have your tests, which technically means that you must land before this date. As far as the wait for both of these: for the FBI cert, the time it takes for you to get your fingerprints done and mailed to FBI with the application, and a wait of around 1 to 2 months to hear back from them; for the medicals, it only depends on the next available day the DMP can see you for the appointment. You will include a form filled out by the DMP in your application but the actual test results will be sent by the DMP first to Ottawa Regional Medical Centre, and then to the VO once Buffalo requests them.