I can't find any pictures of the material sock for the musketeer system. Does that mean you don't really need it?  Anyone got and photos?

Spratt

 Hi - I have been using a modified version of the musketeer system for a couple of years now and I really like it.  Just put the same system on my new boat.
 
I have never used a sock to hold the end of the pole - I use the standard shockcord slider system that non-musketeer Merlins use.  I also stopped using the 1:2 purchase system inside the pole for the launcher - never found a way to reliably stop the rope twisting.  The through deck blocks on the foredeck are just forward of where the puller goes on non-musketeer boats - never had any problems with getting enough forward pull on the mast.  You will need to reinforce the foredeck to take the loads though.  "Protect" tape on the side of your mast really helps.
 
Mark
3797 - fata morgana

Did you try a dyneema bridal in the pole for the block to run up and down? And taking that out I presume the launch rope just goes straight through onto the clew? I had seen a few with the secondary bungee but was sure if it was needed. Currently it looks like the pole comes back pretty quickly....

Yep - it didn't twist every race- but frequently enough that I ditched it.  The pole launch ropes are not connected to the clew, so that bit of it works just like the standard Merlin system.  The launcher ropes run through hi-load Ronstan blocks with a swivel on the mast and then down to Harken hi-load through deck blocks just forward of the cross deck foam beam (I reinforced the foredeck here).  The ropes then run down to spinlock cleats at the forward end of the centreboard case top.  The pole can be launched by either helm or crew without moving from the side deck.  Similarly the spinnaker halliard cleat is a spinlock on the mast with a block underneath, which also allows the crew to launch the spinnaker without getting off the side deck (really useful on a tightish reach as we are only 19-20 stone wringing wet).  Once I sorted out the wrinkles it was very reliable.

Jon Turner uses a 6mm carbon tube inside the pole so there isn't enough space for the 1:2 block to twist. Job done.

Also check out his modified Spiros on the mast using a block above the fitting for a straight pull: positive lockout with much less friction than the standard Spiro setup (where the line has to do a 270° turn around the roller). 

@richard, the 6mm tube is that just to fill the void??