Its not just a question of pure per day (or per diem to be fancy
) expense. Its a question of consistency. You need to consider what IRCC has said when refusing your visitor visa.
"Your purpose of visit is not consistent with details you have provided".
What it means is this (I am being a bit blunt here, because its best to known what you are up against). I am quoting IRCC's intent here.
"Folks who have your profile (nationality, employment, education) typically do not travel to Canada for a 8 day long vacation to Niagra Falls. Those who ask visa for such visit typically end up overstaying or working without authorization. So on balance of probablities, your visa application does not look for the purpose you are stating."
Unless you have substential savings which could warrant such trip, you have a job and income that is much more lucerative to return after your vacation (rather than overstaying) and/or have a history of following immigration laws in the countries where they could verify your visit (typically the five eye countries) it will be hard to get a visa.
That being said, there is such a thing as dumb luck and that is especially true in Canadian immigration. I personally do not relie on it. If you are desparate enough (which I do not see why you should be?), you can try again without addressing the actual underlying reason.
For any really deeper insights, I guess professionals (lawyers and RCICs) will be better suited to advice you. This is particularly true because you have one reject on your record which also needs to be addressed..