Funny I found this now. I have some old reclaimed mahogany (I think) that is not thick enough to make the traveling joiners tool box. I have some cherry reserved for that. I decided I needed more practice first so I cut some old door panels up and removed the finish from one side for a box. This is the first time I have started this process with non S4S lumber. I flipped and went at the other. I did fairly well on two but the third I went very downhill on one end to the point it was no longer viable for a side but may do for a top or bottom. It may have had a low spot with the dark finish that I struggled to remove. I took a reasonably flat side and scribed a line around the board and got to work. When I planed to the line the board is of even thickness but now developed a slight cup. So many things to look at and check during the thicknessing process. I will stay at it, keep trying and pay attention as I go. I must say that I am getting a very good workout doing it this way. My electric jointer and planner are wondering if I am mad at them.