Preferably the 10AM to 11AM slot. 

If I had to collect 14 rent cash payments at once in the neighborhood my properties are in every first of the month on the dot, it's not a question of if I would get shot, it's when.In your situation you can build a strongbox on-site with a slot through a wall or door, maybe in a maintenance closet.

Are there slotted vents in the foundation wall?

The strategy for me is I'll have 50% equity and profit sharing (and expenses) but the conventional loan will only be in her name so I don't use a mortgage slot on my credit.

Do you have rent roll to prove that current slots there are actually paying and on time?

., one way you could free up some slots for traditional mortgages would be to take cash out of one or more properties and use that to payoff other properties so that they are free an clear. 

There's no harm in asking if they have an open slot, or if you can work around their other jobs - that's different.

You can use a multi-tool to cut a slot all the way around the room to increase the expansion joint, just make sure the slot is smaller than the baseboard (or add shoe/1/4 round molding). 

As it is now, I only have one qualifying loan (filling one “slot”), but 15 commercial loans.

If that's the case for you, I would recommend getting it on either your or your wife's name (assuming you can qualify with with income from only one of you), so that you're only taking up one conventional loan "slot" since Fannie Mae/Freddie Mac only allow 10 per person.