Soffit vent orientation

I am the 4th generation to live on the family homestead. I am remodeling the 1916 Sears and Robuck bult home. My question is about the attic. The attick is 28 X 28. 2 X 6 construction. The brace posts, 2 per side, start at 1/2 the way up the roof to near the middle of the floor. I want to take the brace opsts from the / angle they are and convert them to a verticle bracing so that I can put insulationa and sheetrock on the roof and walls. So that I can store boxed behind the bracing and put up shelvs in the center of the floor. How do I decide where to put the brace posts and how many do I need? does it depend on the pitch of the roof? Thank you for any help you can give me. I can take pictures if needed. Leslie:confused:

While attaching pressure treated bottom rail to concete floor, what is correct spacing of nails to this rail? Using power actuated nailing gun. Above rail is non load bearing wall. Thanks.