If making your own OAK kit what are the best materials, are you using dryer vent ducting material or something stronger ? Are you running a standard outside vent like a dryer ?? This will be for an Accentra Insert and I think its 3"...... Just preparing for a self install..I know the sell the OAK kit, but looking at it, I think I can do better just going to Home Depot.. But you guys tell me. Thanx ! ;-)