I am wondering why my first post was deleted?
Anyhow, as I said before, your phrase of 'hatching a plot' was a bit suss. I gave you all the worst case scenarios regarding a marriage of convenience, which one could interpret your primary post as such. DIAC is very aware of those who marry permanent residents or citizens in order to gain residency.
You will have temporary residency for 2 years (partner visa) and at the two-year mark will be asked for further evidence -- or not-- but is totally at the discretion of the Department.
Australia is pretty clamped down now with respect to immigration and you are too old for a 'skilled' visa yet you say you have a business but are looking to retire, ergo a retirement visa might be the route to go. Bear in mind that this is a temporary visa and doesn't give you PR. Yes, a partner visa does but you will have to reside in the country for more than 6 months at a stretch if you want PR; even then, the visa is valid for 5 years and you must prove substantial ties to the country in order to be granted a RRV (resident return visa) when you re-enter after the visa expiration.
Note that your future wife will be the one sponsoring you and she has to prove she has the income and capacity -- NOT you. I presume she is an Australian perm resident or citizen. It's a moot point if you are the one paying and supporting her from the onset. Who has Canadian citizenship?
I have not sugarcoated my answer; hope it's cogent enough... This may be redundant however you are must be aware that immigration is a not a right but a privilege and Australia doesn't have to bend it's rules to accommodate those wishing to migrate here. If you are on a partner visa and decide to spend less than 6 months here, your visa will be scrutinised (see above).
To reiterate, if you are less than truthful, you and your 'girl' can be charged with criminal conspiracy. This is the worse case scenario. Let's just say I am quite cogent in the area of law enforcement... DIAC also monitors forums such as these with regularity, that is a fact!! Individuals from high risk countries are put under a microscope more than those from low risk, an example being Canada.
It appears that there is a retirement visa (405) if you fulfill the requirements which entails having assets of and above 750,000 aud and an income of 65,000aud. You and your partner only can be on this visa and both of you must have no dependents. It is a 4 year visa. In the interim, you could and will be prevented from entering the country on a tourist visa as Immigration will question why you visit too often.
Your best bet is to check the 'immi' site and use the Wizard, rather than calling the Embassy's call centre and be given different responses that might not be the fit you are searching for. A '309' is an offshore partner visa, btw, so you might wish to look at the online booklet and carefully examine it's contents as to the requirements. There are stringent checks and balances in place, ie security checks and your passport(s), past addresses, work history, travels etc will be under the microscope. Everyone has to fill in a Form 80 which asks for info from you family, your siblings and every movement you have done since leaving high school. It's a very detailed process and time-consuming. There are no short cuts in any visa process and there is no wriggle room.
Good luck.