Doug,
if you go to reference section under main menu then look at past bulletins there are a number of articles on raising/lowering masts. The main thing is ensuring that the shrouds are kept taught during the process, as the pivot points are different for the mast foot and shrouds this entails making an arrangement to raise the shroud attachments, either permanently or temporarily (https://drive.google.com/file/d/0B7zprD7rUaoBNFZsRFd1eUxDMTg/view?usp=sharing) if I remember correctly in one of past bulletins someone had devised a temporary solution using wooden batons, I have raised/lowered A90s mast in past but after dropping and smashing the old wooden mast when a shackle gave way I decided that for the number of times I raised it in a season it was safer to have it craned on and off. I know Trevor (T10) lifts his mast using the spinnaker pole for leverage which is what I believe was the original design concept