Building Duplexes / Need some advice

[Drake Siegel]

I have the opportunity to purchase 16 lots that are zoned for Duplexes. The market rent needs to be around $1,800 per side and no more than 2k a month (depending of finshes) I'm having a hard time getting someone to nail down a price on construction cost. The other unkown variable is the city and county taxes. They seem to be no help just on plans. Does anyone have experience in this kind of project. Would like to be 1500 square ft a side with 3 bedrooms 2 1/2 bath. In my opinion the building cost needs to be around $125 a square ft. Not sounding like it would be fiseable from who i have talked to this far. Any one have recent experence building Duplexes? Thank for the help