They do not want the dark value with no tenant value to be less than mortgage balance at end of the primary lease term.You want to look at absorption  and comparable rents for industrial in the area to see how your property stacks up.If you buy at a high cap rate you want to look at the option periods for the current tenant in the lease.

As you get to know some of the folks offer to trade some free labor/time to be able to shadow them and learn from them.  

People want a place to look bright, not dark and dingy.

When you start cutting into it, unexpected areas can go dark.

I'm new to real estate investing / wholesaling but I would like to expand my knowledge and hopefully Shadow someone through a deal?

you could actually paint a black line where one unit ends and the next begins, then choose colors that look good together...light gray, dark gray, tan, brick, green, colonial blue, like bm historical colors or some other palette.

Their expertise minimizes your risk of a bad situation, and your choice of project will be less of a shot in the dark. 

And know that mixing business with friends is a great on one hand, but can cast a shadow as well.

But just a random stab in the dark they want you to overpay IMO 500 extra for the headache of a STR isn’t worth it, plus you’d have to furnish it and pay for all the utilities.  

Very dark inside I will add natural lighting upstairs with sky tunnels.I will offer lower after 153 days on the market the price is still high and pay like 20% down to operate on breakeven basis.I do not anticipate homes of this vintage or neighborhood homes to appreciate much.