One thing I didn't think of, we have a lot of apartment buildings in D areas, one area in particular with several hundred units. 

I suggest you avoid TD based on my recent experience with them for this particular purpose - I continue to use TD for lots of other banking. 

PenFed does 80% on non owner occupied HELOCs.

I second that it's more important to find a good CPA who understands real estate investing than someone in a particular state. 

That means: this particular buy was not a good BRRRR candidate, but, may still give you an acceptable return on your outlay anyway. 

Great credit, zero non-mortgage debt, only 2 mortgages. 

Hey there,I've been searching properties in the upstate of South Carolina for several weeks now (and I feel somewhat dumb for even posting this to begin with because I actually own a few rentals and I'm slightly terrified come tax time next year), and apparently I've been running my tax numbers all wrong and not accounting for the 6% non-owner occupant rate.Am I completely missing something or does this seem to kill virtually every deal out there??

A non professional said they fail.

It really comes down to being educated about the potentials and risks of RE in general and a given niche (apartments in your case) in particular.

the proration requirement is all the gain prorated between all the qualified use (as a primary residence) and non-qualified use (as an investment property.