Those of you looking for some alternatives to make smaller batches of koji i can across a website whilst looking into other ideas for culturing koji and this one popped up
Basic setup of a thermostat connected to a slow cooker so the slow cooker turns off at the specified temperatures. This should keep the heat more evenly spread as the ceramic holds the temperature pretty well.
All that would need to be added is something to control humidity like a water pan placed somewhere. Thought this would make a more viable option for some people who don't want to invest a lot of money in growing there own cultures and had a slow cooker knocking around.
Anyway, hope again this helps people out.