I switched my Daedelous Magpie from Scotch (flyer led) to Irish (bobbin led) tension last week. It was so easy, I think it took me 15 minutes, and that included double checking instructions to make sure I was doing it correctly.
Getting my hands to remember how to spin in Irish tension was another story. I don't have an Irish tension wheel, and don't use Irish tension on my Matchless much. I won't lie there was a bit of tug-a-war, before I finally took the brake band off, then it was much smoother for me. The Magpie has a strong and steady pull.
What is a favorite yarn of mine that is happiest when it's quickly pulled onto the bobbin? Low-twist singles. I grabbed a braid of BFL from Frabjous Fibers (the color is Tourmaline) and spun. This is a prefect set up for low twist. It took some discussion between my hands and the ammount of twist, but I found the sweet spot, and I burned through four ounces in no time.
Here's the yarn before I finish it, just a few kinks and barely a twist in the skein. I soaked and whacked it, which helped the BFL to bloom and fuzz and stabilized the singles a bit. It's about 6-8 WPI.
The Irish set up on the Magpie is great for low twist yarn, I could dial my twist way down and the strong pull got my yarn right on the bobbin. I'll be spinning more yarns this way. My next experiments with this wheel will be with textured and art yarn.