How to look at landlord income

[Amie D.]

Kind of a funny question - but I am a landlord, and will be looking to rent a house or apartment soon. I haven't rented since before my rental income was a major part of my earnings. How do you all look at a landlord's rental income when screening a new tenant's income? I have property managers that screen tenants for me but even still, all my tenants have had mostly income from W2's. 

Also what counts - the actual income I get from rent, or the rent minus property management and other maintenance fees? Also what documentation is best to show? 

Also inconveniently, tenants are moving out at the end of this month, so one of my houses will go vacant (for the first time in five years). Is there any way I could show the steady rents during the gap until I get new tenants? The current tenants are refusing to allow new potential tenants to view before they move out, citing it is "too stressful" (in violation of their lease), as well as now citing unreported repairs, so it looks like there might be an extended vacancy time due to this as well. 

Thanks!