I would think you could also adapt some kind of feather board or hold down (bench dog holes along one side?) to that hand saw bench for when you get closer to the end of the board. Just be patient when ripping with a hand saw and let the (sharp) saw teeth do the work. You're not framing a house, so take it easy. Doug Fir is good wood for stuff you want to keep straight. It used to be the wood of choice for all house framing until we started using faster growing pine. Tear an old house apart and see just how straight the 2X4's stayed!