You might want to look into replacing the motor with a servo motor. In my opinion they are much easier to use and with the speed control box much more controllable. The big industrial motors have extremely sensitive clutches. This is similar to the one I changed ours to
http://www.ebay.com/itm/131533547404
You can set the maximum speed with the knob. The pedal they come with is still fully variable, but only up to the maximum speed. Makes learning a lot easier. Here is a genuine Consew one too
http://www.ebay.com/itm/151695455948 - it just has push buttons instead of the knob for the max speed adjustment. They are also a lot lighter and more energy efficient than the big ac motors.
I have one of those hem folder attachments somewhere or another. Had it on there for about 2 weeks and took it back off. Did not much like it and as someone else mentioned - I also thought it was a pita to use. Nowadays we just cut banners with about an inch to an inch and a half of extra material all the way around and just fold it by hand as we run the banner in. Its actually pretty easy once you get used to it. It can be easier if you use a hard roller and crease the material on your work tables ahead of time though.
Like I said, the servo motor will make things a LOT easier to control. Especially when you are getting used to running it. Speed while maintaining accuracy will only come with time and experience. If you try to go fast right now your hems will be all over the place wandering left and right like crazy. We have a wholesale place here in town that does finishing work for a lot of shops - couple of older women in there who have been sewing for many many years - its crazy how fast they can run the machines. Literally wide open as fast as the machine can go and they stay dead on straight. I've had our machine for a few years and still cannot imagine running ours at max speed. At max speed the thing is literally scary fast!
You also want to stock up on a few packs of needles, spare bobbins, at least one spare bobbin case, and some sewing machine oil (I use zoom spout oil which makes it really easy). I've not seen pre-wound bobbins with the #69 weight thread we run so its pretty much "roll your own". As long as your table came with the attachment its very easy to wind them though. We also run both black and white thread depending on the banners. We usually keep about 5 to 10 bobbins pre-wound and ready in both black and white and keep both black and white spools on the machines spool stand. Only takes a minute to rethread the machine for a different color.
