This one I try to keep in top notch condition.

Welcome to the BP family; appears you have all your pieces in place.

It's a tri-plex and I would be living in one of the units while the other two would rent for 500 a piece.

That means if the tile is 24 inches long, the end piece of the tile on the next row must not go over 8" (and 6" would be better) from the end of the piece in the current row.

I take little bits and pieces from each man I meet like this and apply it to my own business.

You could park this on a small piece of land just about anywhere.

Maybe it is part of the liability piece of it they are now concerned with; it seems something else is at work in this now.

Have you tested the stain on a sample piece of the same material as the floor?

As far as estimate goes, for smaller job, I know small (most likely single operator) specialized contractors usually just do it either on a piece of paper, or carbon-copy setup - all hand written. 

But I can definitely appreciate that the variability is in the approximation of rehab costs as each investor would put their own unique perspective in on that piece of the deal.