I think I see where you want to go and I don't think you can get there from here. Every chart and calculator I've ever seen tells you what temp to cook at. There's no way to input a higher or lower oven temp.
Bottom line is that you have to draw on your experience and other resources for "standard" oven temps (e.g., 350o), compare with the times you're familiar with for "low & slow" (e.g., 225o), extrapolate the result and throw in the MSU* factor to come up with a guess.
*MSU: Make Shi Stuff Up.