So then the question is, what is the math that goes into finding the optimal building size?

Learning from others first would be optimal!

I'm purchasing the house without a financing contingency, so if my lender says "no" for some reason, I'm still stuck with the house or losing my EMD.I've had to point out to several highly experienced real estate agents in this area that no checking the boxes for financing is NOT the same as an offer that I'll be paying cash for.To OP, it's possible that your HML's POF letter is written sub-optimally and that some minor modifications would satisfy the seller/AM.

When rates are increasing over a cycle, it's usually because employment and lending conditions are improving, optimism improving, more cash on hand, oftentimes more than offsetting higher rates.What I think we can say with a high level of certainty, is that in any given economic backdrop, lower rates would very likely cause higher prices, and higher rates would very likely cause otherwise lower prices.

@James UryckiHello and Welcome to BiggerPockets, the Best Real Estate site on the web.

still have some friends in Montreal, most of whom are involved in IT or Web design.  

@Brit Foshee  thanks and also visit our web for automated seller leads . 

I created web sites for property managers for a while and they readily available.

Over 2000 in DFW.Please look up ONEprop on the web.

Without any business information on their web site, it is hard to know who these people are.