I have clients who would be at 40% or 44% with just their primary home and day-job, but between all the rental income their mortgage calculated DTI, calculated properly by folks that know what they are doing, is down in the 20s, 27% or whatever (24% to 29% is a range I see again and again, for whatever reason, possibly a result of people trying to follow the "1% rule"). 

It just depends on what you need and whether or not you know enough to take care of your private lender properly.

Also, there is a difference between working and working properly.

You are moving too fast to buy and this is how people get themselves into terrible deals without proper representation.

Make sure that the water heaters are vented properly. 

If you are not experienced with real estate contracts in Canada, here is my advice...You should be working with a lawyer to have contract of purchase and sale paperwork drawn up properly (or at least review to make sure you are not putting yourself in an unfavourable situation) and have a template for going forward or be working with a realtor.

We jumped into investing with our first property without the proper knowledge.

If they accept, coordinate with them a date and time along with a locksmith so as soon as they are out of the house the locksmith can simultaneously change all the locks to the house.

@Mark RechkemmerThe internet will tell you this is possible if structured properly. 

If the owner is ok with the realtor doing this and the realtor properly discloses to the owner exactly what he is doing, then there is nothing wrong.