X2...I've had my CB4500 I got from Bob in Toledo for 6 months or so and I'm super happy with it. like you PastorBob I never used a sewing machine in my life so initially there was a somewhat nervous learning curve as to how do I get his thing to do what I want it too. mine came from Bob set up the way I intended to use it, #25 needle-277 thread so it was just a matter of gluing up some samples and start practicing...a lot of samples and a lot of practicing ha ha.
Today I feel pretty confident getting on it and stitching up holsters and sheaths. I think my blunders are in the past. I'm a knifemaker by trade so I don't use it everyday but last week I stitched up six sheaths one after the other, set them out, and looking at them I thought about if I had to hand stitch those, my eyes and hands would hurt and I'd probably still be on the first one. I hand stitched for over 30 years and it was past due I got a machine.
I would say glue up a bunch of scrap different thicknesses and practice a lot getting to know your new machine, you'll never look back.
Congratulations and good luck!