Hi Guys, I’m in the process of putting together a 2x4 stand for my rimless 57. I have a question for all of you woodworking experts out there... What is the best and easily sandable wood filler / putty for covering over finish nails and panel nails in trim pieces and 1/4” birch plywood skin? Also, what grits of sandpaper do you recommend. Do you let the filler dry fully before sanding? I will be priming and painting the stand white and want as clean and smooth a surface as possible before applying paint. Thanks!