ADU in Colorado Springs

[Canneton Howard]

I bought a duplex unit in Colorado Springs about 6 months ago and want to continue to grow my portfolio but with prices going up, nothing in the area is making sense to buy at the moment. However, the lot that this duplex is on is plenty big to build an additional 1-2 units (detached from main unit). 

It is currently zoned as an R2 so technically I shouldn't have any issues building an ADU. I would however like to maximize my ROI so ideally I would like to build another duplex. Obviously this would depend on getting it rezoned to an R4.

First of all, has anyone recently tried to rezone to an R4 in El Paso county and what was your experience?

Assuming that I can get it rezoned to an R4, is it worth the extra costs/hassle to go this route?

I've started talking to a GC and according to him, the fees associated with 1 tap vs 2 jumps from ~$5500 to ~$19000 along with other fees and red tape. He's finishing up building a duplex on his own property and says he wishes he'd gone with just a single unit.

Has anyone else gone through the experience of building additional units on a rental property (or your own property for that matter)?

What $/sq ft should I expect for something like this in this area?

I appreciate any feedback the BP community might have on this.