gaff rigs

I am converting a 3m tender that can be rowed and motored with a tender to a cruising dinghy. I plan to use a gaff rig with a 3m tall mast and a 2m luff. I plan to use lee boards. with the mast 60cm from bow and a small foresail atatched to a 30cm sprit where should i place the leeoards to...

Has anyone tried making mast hoops from washing machine / dishwasher discharge hose (or something similar)?