I've made some of your tweaks (left and right central defenders but kept the middle one in central defender stoper / wing backs in defend) and it's working really well.
I'm playing with Hamburger SV and after 24 matches, I've lost only 1 friendly match against Man City (0:1), 2 draws against Juventus (friendly) and Barcelona in champions league and won everything else.
That's outstanding, considering my team as a good one, but not the best at all.
i am very glad that works for you! ive tested it with big teams and very small teams and that was working for me as well! i think mainly switching the central defenders! couse ball playing defenders are standing gigher up the pitch so it creates more chances for overlong balls and easy goals to concede, but as well they have more abillitys to create some attacking options! so for big teams BP-defenders could work very well but for underdogs i highly recommend switch for central defenders