Dave:
From your questions I assume you are doing a two point splice (the easist for the beginner), If so the old timers said to have the points parallel to the growth rings, but I don't know if its important except for looks.
Your Osage will make excellent footing. As to rounding the foots, that can be done a number of ways, probably the easiest is a very sharp block plane. Take a scrap piece of 2X4 and cut a "V" groove down the middle. Place that in a bench vise and the shaft in the groove with the foot pointing towards you. Now just start taking the corners off the footing, turning the shaft slightly after each cut. You do want this as accurate as possible. You will eventually get down to a multi sided foot that is almost the right diameter. Now make what I call a sanding book. Its nothing more than two pieces of 2X4 hinged together, a hole down through the middle 3/8" or slightly larger. Line the hole with sand paper. Then chuck the shaft up in an electric drill place the footed shaft in the book and start sanding, until the desired dia is reached.
Bob
P.S. Woods like Osage are best glued with Epoxy not wood glues.