I wouldn't worry about it too much, it conveys respect, or is meant to.Work with an attorney to develop a general contract with boilerplate language. 

May I respectfully ask what the average cash flow on your properties for you to view $250 or more per month an unacceptable number?

If so, I would very strongly consider the merit of taking on $300k in debt in order to achieve this level of earning potential and perhaps explore cheaper ways of attaining this education.Rather than thinking about how you can mitigate a poor financial decision through real estate, I respectfully suggest that perhaps it's better to not make the poor financial decision in the first place.  

A lot of forum members are experts in their respective fields related to real estate investing, whether that is real estate sales, wholesaling, flipping, buy and hold investing, lending, self-directed IRA and Solo 401k investing, or tax and legal guidance.There are some pretty nice discounts on many products and services offered as Perks to BP members that you might want to check out: https://www.biggerpockets.com/perks/proIf you haven’t been to it already, the Bigger Pockets blog features links to their fantastic podcast and many great articles: https://www.biggerpockets.com/renewsblog/The site has quite a few tools that can be helpful for new members.

Remember, real estate investing / construction / this industry as a whole are about building relationships, so treat people with respect and those relationships will grow well. 

Mutual respect always goes a long way in business.

And then with respect to the lender, is it a roll of the dice to notify them, or is it prudent to make the “subject to” deal solvent and viable?

If you have any great recommendations with respect to Canadian based books please feel free to let me know. 

However, in my opinion, and experience you need to learn and gain a great understanding, of the various municipalities, with respect to demographics, pocket market appreciation/ depreciation, pocket market economic factors, demand for the need to rent, the needs of tenants such as close access to transportation and shopping, vacancy rates, etc.

They don't have the insight to forecast markets, lack respect for downside (because they haven't been around long enough to have experienced it), and underwrite to the best-case scenario.