I'm getting ready to start on my scratchbuilt UNN torpedo, and I have a problem. I have fins that have a central crosspiece, with two pieces attached at the ends at an angle. I have no idea how I am going to join the pieces. I really doubt I will be able to use a sanding block to get all the angles correct. Is there a better way to cut the pieces at the proper angles so they align correctly? See rear view picture.