Dilis,
Without doing calculations my guess would be 1/4 inch 1x19 wire for standing rigging or, if you go with synthetic standing rigging, 5/16 dyneema or vectran. For your mast, recommend you go check out a local rigging shop in your area. They usually have a stack of old spar extrusions they will sell for cheap. For instance I bought a 38 foot tube of 7.75 x 4.5 section for $200 from Annapolis Spars. E-bay is also a good source of used spars but getting a mast shipped is a problem. good luck,
Kevin