The way I came up with the numbers was using a conventional amortization schedule and summing up the total amount of interest over the term of the loan (360 months), then dividing that amount over 360 to come up with a fixed monthly interest and hence a fixed capital amortization.

Everybody has their own strategy - here's what I do:Property Tax Reserve - this is simple...take your estimated property tax and divide it by 12. 

Hence take your budget and divide it up over that length of time.

Then you can divide that number by your floor area and see if your way out of line vs nearby comps.

The trick is, I too am busy with running jobs that has in-house crews, so I'll simply act as your typical GC or commercial GC / paperwork contractor on this to divide my time, I could fill out the gaps but I couldn't use majority of my workforce because i have deadlines also, i could fill in a tradesman or two when there's a hiccup, say when a plumber or electrician doesn't show or keeps pushing the schedule out, but that's about it.

That cost can be added in as a separate charge on each lease, divided among tenants according to the size of the unit they lease; but that charge needs to be referenced in the lease agreement.  

If you are going to make the commitment to marry and take the risk you should be prepared to divide 50/50 if the marriage lasts longer than 5 years.

Then divide that by purchase price to get the ROI or CAP rate. 

What's left (heirs' equity) gets divided up "per stirps" meaning you get what's coming to you, net of the costs. 

You could divide by the numbers of units.