I have installed two of the halyard block set ups from Jerry's drawing on different boats. It is a great mod... Have not had any issues. One change I would consider how ever is to make the jib halyard block lower than the main. The reason is twofold; one is to increase clearance between the block and the furler's luff tube and if it is a couple inches lower it will eliminate the need for a halyard wrap preventer. Like I said it works well as is, but if I were to have another made I would lower the jib block.
Mike
C227