Dennis is going to be the final authority on this, but I have only ever seen one truely "V" shaped forearm and it was uncomfortable to hold. I would just make the forearm a little more "V" than "U" and make the nose piece as you always do. That is, swagged one piece if no groove (although a two piece is probably more common on 19th century guns) and a two piece if grooved. The nose piece should match the upper forearm. Actually, on my rifles, the nose (before the nose piece is added) is the model for the profile of the rest of the upper forearm. I try to make it perfect and then extend the shape down the forearm. The nose piece should, ideally, look like a metal skin on the forearm with a smooth transition from wood to metal. Usually, it is not so smooth or perfect, but that is what you are shooting for. ;