I visited the Leather Machine Co. Inc. today. They are very busy with trade shows. It was fortunate that Steve Tayrien was there. They had just received a shipment of machines and so the shop was full of crates. Steve showed me around and answered all my questions. The choices for me from Cobra are the class 4 or 18. I need to still ask about the feet. I will be doing work on leather, some veg tan, and do not want to mark the leather with non-smooth feet and feed dogs. Steve said he could provide feet that are smooth. Time to go back to the cave and cogitate some more.