You should do your best to make some estimates first about your future potential revenue, taking into account how much business you were turning down before, to make sure you will have enough business to make it worthwhile.
Just breaking even for the next fifteen years would suck, and you would get tired of it.
I'm not saying not to go for it, because it could turn out to be awesome, but I am saying that you should be careful....
Kind of tough to speak details in this forum. I'd end up writing an essay which nobody could read anyway.
I'm trying hard to be careful here, but the business planning seems like trying to look into a crystal ball as there are many factors that I don't control. The building allows income streams that were never possible before. My senses tell me to go forward, but to some extent the business planning may have to be done with hindsight. It's like jumping into a pool, with the confidence that you'll learn how to swim.
Years ago, I was frightened when I bought my home. I did it anyway, assuming it would turn out for the best.. It turned out to be a very smart financial move, made my life easier, and allowed a good bit of personal growth in ways I didn't anticipate. I'm kind of assuming the same will happen with the purchase of a building.