Sorry, PS. Friction knots on flouro need to be longer and tighter. I think you could get away with a PR down to about PE 1.5 - 15lb leader. Below that I'm not sure, you might cause too much damage to the leader itself. Could well be wrong on that though, just my opinion.
You can make a very cheap PR bobbin from a fly-tying bobbin and an empty thread spool. Just wrap the arbor of the spool with insulating or duct tape so the PE can grip it. You need the PE to come off the bobbin under tension so once you've wrapped enough round the spool wrap it a few times round the bobbin leg. The bobbin should stay tight to the shock leader as you spin, there should be no PE line visible between the tip of the bobbin and where the wraps are forming.
The knot should be around 4-6cm long. I don't like to have it on my spool when I cast as i feel it causes too many wind knots.
Hope all that made sense.