Lots of good things I really didn't consider. Thanks for the insight. Yes it will be direct drive. My brother mentioned his technique for assisting the drag was to apply palm pressure on the outer lip of the spool, so I designed with that in mind. I'm assuming your method is to pinch the spool cheek and frame with your thumb and index finger to add drag, correct? If that's the case do you prefer a smaller knob to prevent interference when doing that? I could definitely design future spools to have an ergonomic groove on the cheek. The frame is mainly 0.125" thick in most features but is 0.063" in some areas for rotating clearances.
I've been working on the mounting foot, but encountered the need to make some mandrels and fixtures to properly hold the workpiece for various machining operations. This really is a learn-as-I-go process. I'd love to have CAM and CNC tools at my disposal, but I just use my equipment for hobby work 90% of the time and can't afford the fancy stuff. I'll try to post some more pics hopefully this weekend.