I have a dynaking pro and the dyna king side winder, with both sets of jaws.
I picked up the sidewinder when I started tying commercially.
For tying streamers, you'll notice an immense difference in tightness and speed.
A tip for tying rotary that I was taught from the fella I worked for.
DONT use the bobbin holder EVER! No half hitches either. really there's a time for it, but its pretty rare. I've never needed one. I would bet you can do the same on the renzetti's. I'll report back next week when I get my hands on a traveler while I'm down south.
example, you're doing a wooly bugger. Tie in the tail, tie in the hackle, tie in the chenille. Take a turn or two of the chenille, now hold the bobbin and material in your right hand (for a righty) and spin with your left. I like small ceramic bobbins, mediums are usually too long for my short fingers. The thread goes right in front of the chenille, the body is almost glued on! I've seen guys hold it a couple different ways, they all work. Its a bit goofy at first, and harder to explain than it is to do.....once you figure out how to hold, you'll be in. For the hackle I let the bobbin hang, being there's only 5 turns or so there's no need to use the holder here either. Its faster to back off a couple turns if needed than use the holder.
Works well for any similar streamers, fur, chenille etc.
I've never tied on a Renzetti, only the dynakings, a regal which imho is terrible for comm tying due to the heavy spring, I comm tied a couple winters on it and destroyed my hands! a superior 2A when teaching, and of course the Thomson that came in a kit when I first began.
The other downer of the regal is shooting small hooks at mach 5. its fun once, good luck finding the blasted things in the carpet LOL! In my case it was a barracks room. Things didn't go well during health and welfare inspections. Something about totes of dead critters skins and feathers along with hidden hooks. fun times!
the only downfall with the sidewinder is the adjustment mechanism is in the way on smaller or certain flies, mostly presentation which I do very very little of. I bounce regularly between the two. True Rotary for certain patterns will really speed up your tying if you're interest in comm stuff. They are worth every penny!
I'd really like to find a handvise....if anyones in south central with something like this I'd like to check it out.
http://www.paflyfish.com/forums/Open-Forums/Fly-Tying/Hand-Vice/5,15416,compact.html