It may be more time consuming as an allocation needs to be done on each taxpayer's tax return, but certainly not "complex". 

The allocation of the income will not affect how it is taxed.

., perhaps I am allocating too much to CapEx each month?).

A portion will be allocated to the period of non-qualified use.

You'll also experience them pulling your interim construction loans because their allocation gets full or they decide to shift their portfolio in another direction.  

If you are / know one, please contact me (would love to partner up - have some ca$h to allocate).

The computation of the percentage allocation or split is generally done by using square footage, acreage, or some other methodology that is defensible should you be audited. 

Divide the costs up by four and allocate a portion to each property?

What I would say relative to Greg's comment is, I wouldn't buy a property if I couldn't allocate those expenses like an apartment building because based on friends experiences, the costs are double if a tenant isn't paying the bill because they generally don't care.

. - I have seen Capex and Repairs as 2 different expense items in calc worksheets - around 5% allocated to each.