hi mohit
i don't think think you should be concerned about your backlogs. once university/college accepts you, backlogs/marks are not the criteria on which a visa officer decides your case. they are also concerned with your finances, your ties to home country i.e they should be satisfied that you have something to came back to your home country.
i have known many friends who scored near about 50% in their +2, bachelors and had many backlogs and still got visa. don't get dishearted. Atleast apply once, for you have more to gain then loose. attach a good SOP with your application and make a good representation especially in "study questionnaire" section of visa application.
as regards to where to apply- i would recommend a university. firstly focus only on universities and only if are not able to get a university, then move to colleges. and also try universities in provinces like Alberta, Manitoba, Saskatchewan,quebec(though quebec is french province,try concordia university as it a english language university, some more may also be there try researching).also once consultant had told me that if you secure admission in quebec, your visa chances are almost certain.but still it never is 100% certain . because not many students go to these provinces as majority of them choose ontario in general and toronto in particular. so because of less competition you have more chances of securing a seat. i have heard that also sometimes VO's favour your application in these provinces because they need more manpower/human resources in these provinces.
and at last do what you think is best for you.
best of luck