Kelly, each one is a little different so you will have to get a feel for them. They usually do come out close in weight and size. Just reduce the diameter of the butt end a bit with the thumb plane. I usually bring them down to 11/32" to 3/8". If you are going to use a field point or store bought arrowhead this size makes it easier to fit.
FYI...the arrow in the picture has a viburnum shaft(notice the opposite leaf/branch scars along the shoot) and not a sourwood shaft(alternate leaf/branch scars). I sent it along to Kelly so he could see how I made arrows. Each shafting, sourwood and viburnum has its own dos and don'ts but their arrows both shoot well.
Did I send you any green shoots? If so, go ahead and scrape off the bark. It is a lot easier green. Most other shoot material will check if you do this right away(at least in my experience)but not sourwood.
Steve Parker(Hillbilly) planes his sourwood shafts down to 5/16" and shoots 45# to 55# bows. BTW, they look like machined shafts! I, personally, prefer the more natural look. They all shoot well if made well!