I just finished a 2 million dollar house, and we are trying to decide between copper or wood. I know that wooden gutters are available in douglas fir. I am trying to find them in either western red cedar or alasken yellow cedar, they should last 50 years if installed properly. Stainless steel bolts into the rafter ends is more then enough to secure the gutter. Useing Sikkens or Penofin before installation and all cuts should protect the wood. Proper pitch will keep the gutter dry ( no standing water). Use copper leaders and downspouts.