If it was important, then I would buy the roast, thermometer, and stopwatch (#2). While the thing was cooking, I would work out a formula or simulation for the

If it was important, then I would buy the roast, thermometer, and stopwatch (#2). While the thing was cooking, I would work out a formula or simulation for the process as in #3. Then when finished with both, I would make a series of calls as in #4 to see whether the common wisdom matched up with experimental and analytical reality.