I am building a 14 foot rowing dorie.  I have three vertical ribs 1 1/4 inch wide at which I plan to back all scarf joints.  My attempts at cutting the joints on scrap plywood has demonstrated that a long joint (10 degree) is much more variable than a 45 degree joint using a bevel attachment on my planer.  My question is if I go with the the 45 degree with screws on both sides of the joint, will this be as good a joint as the 10 degree and a single line of screws through the joint.