Most people here are choosing the stable 9-5, high-paying job, retiring in 10-20 year path, versus investing in spec homes. This isn't really the place to ask this question, not to mention with very limited information.
I mean, it's 12% of your net worth, and it's almost guaranteed that you won't lose the full 12%...the question is determining the upside AFTER including your own time spent on the project. Only you can decide if it's worth the risk or not.