I think you need to figure out how much rent you can afford per kw.

Then figure out how much fan you need per kw too.

Mining at scale is tough.  it's a lot of capital in, and you are competing with garage miners with no overhead.

If you are signing a long term lease, look at whether you could survive another tough period like 2014-2015.  The odds are good that it is coming.

Good luck.