Devices like the one you describe tend to make things much more complicated than necessary. I have been raising and lowering my mast on my H-16 for years. It is not difficult to stand on the tramp and raise it. The trick is tying a line about 6 or 8' long to the jib halyard and the bridle before you start. After raising the mast lean down and pull in the jib halyard and tie it off on the cleat. You can then get down and fasten the forestay. Make a tripod that you can set the mast on to hold the weight off the traveler track and be sure the shrouds won't hook on the pylons as you raise the mast. Lowering the mast is the reverse. Just remember to put in the pin. Everyone forgets to put in the pin once but usually only once.

Howard