Analyze land deals as an owner-builder for a house hack?

[Mindi Rosser]

Based on Oahu, we're looking to buy a piece of property zoned for a duplex and build on the property with the intention to live in one side and rent the other. If this model is successful, we'll repeat every few years. My husband is a journeyman carpenter and could build the house himself with minimal help (plumber, electrician.) We'd rather go this route than a more traditional fix and flip or straight-up house hack. 

Is there a calculator or analysis tool or resources you've come across for calculating costs and returns for buying raw land via a land loan, getting a construction loan, and then refinancing the house when it's finished? 

There are a good number of variables, and this is our first time going through this process. Just want to ensure we're doing our due diligence and not getting in over our heads prior to the project and be sure we have enough set aside at the start.