I am planning on using mast + sails (and whatever else I can) from a 505 dinghy. One issue this presents is that if the mast is stepped on top of the cabin with the vang attached near the bottom of the mast, the boom will be very high. Although this might seem nice for avoiding cracked heads it means that the heeling force will be larger and, more important, the main sheet will be very vertical when close hauled. To get round this it might be possible to use a gnav system and put the goose-neck just above the cabin roof, though this might be just too complicated. Alternatively (or as well) the main sheet could be attached to a traveller system.
The reason for wanting more sideways pull when close hauled is so that letting the sheet out in a gust doesn't automatically make the sail fuller