Residency for tax purposes is a question of facts. It is not something you can apply for. (But see below)
In the circumstances you mention, provided you really do sever residential ties to Canada when you return to your home country, I don't see why you could not be a non-resident for tax purposes for these years. I don't know if you have any capital assets but if so you should talk to an accountant because there may be taxable capital gains when you go non-resident. Failing to declare these and pay the tax due is a common reason for the CRA to deny someone non-resident tax status.
Although you cannot apply for non-resident tax status you can apply to the CRA for a ruling on whether or not they consider you non-resident. They will not do this on a hypothetical basis - you can't ask them "if I do this will I be a tax non-resident?" You can only ask them "these are the facts at the moment, do you think I am tax resident or not?"
In reality, if there is not a great deal of tax involved, you file all your returns on time, and pay all your taxes as they become due, you fly under the CRA's radar. They accept the dates for leaving and returning to Canada as given on your T1 tax returns
This information is useful,thanks!