If it's just coming out too cold, that's not altogether surprising, messing around with multiple parameters can be unpredictable in that way. Either double the CO2 value or increase stellar flux by, say, 5% and try that out, and if necessary keep doing that until you get to at an average temp of least 10 C after 10 years into the simulation, then you can keep tweaking for more precise temperatures. I also have an example of a script here that will automatically adjust CO2 to get to within 1 C of a desired average temp, but it can take a while to run https://gist.github.com/hersfeldtn/f...645dfe759effd5

I've run across OASIS in the past, it's worth keeping an eye on but it doesn't really have anything ready for public use so far