It is very straight forward and easy. I used 7/64 Amsteel for the internal lines and 5mm swiftcord for the line you pull. I think the 7/64 Amsteel reduces friction in the system a lot. The downhaul eases much easier. The general steps were:
1. Pull diamond wires off of spreaders.
2. Remove rotator arm.
3. Remove mast base.
4. Remove spacer tube and washers for rotator arm.
5. Remove bolt about 4 feet up the mast and pull downhaul out of mast.
6. Draw simple diagram of how the lines run. It is not complicated at all.
7. Cut new lines to the same length as the old ones. You can change the length of the line you pull on. I tried a little longer but after sailing cut it back to about the original length.
8. Run new lines per diagram.
9. Find something long and thin that you can cut a small groove in the end. A broom stick would work well.
10. Wedge the mount for the internal blocks into the groove and slide it into the mast until you can put the bolt back in.
11. Put everything else back together making sure you keep the lines running nicely. Not twisted or wrapped around anything.