How to make windows of new folders open in my size?
I mostly use column view and have removed all folders except the home folder from favorites, so the root folder of most windows is ~ or /. When the default dimensions or view options for them change, I reset them by running this script with FastScripts.

tell application "Finder"
    if number of windows is 0 then return
    tell Finder window 1
        set toolbar visible to false
        set sidebar width to 0
        set statusbar visible to false
        set current view to column view
        set bounds to {474, 250, 1318, 750}
        tell its column view options
            set shows icon to false
        end tell
    end tell
end tell


FinderMinder watches what windows you open and changes their dimensions. The windows appear at the previous position for a split second though.