If you want your brakes set up correctly, then you can abandon any thoughts of just squeezing the lever and tightening the bolts(if you’re lucky enough for it to work for you then i’d suggest you buy yourself a lottery ticket too),expecting a thin strip of steel to stop the caliper twisting is asking a bit much really.The method I use (many times a day, every day of the working week, every week of the year, i’m not bitter, honest)is to loosen the caliper just enough to allow movement, sight down the rotor, hold the caliper so the gap to the pads is even at all points, and nip the bolts lightly.The caliper will probably move, so loosen just one bolt a little, move that end a touch in the right direction, then do the same at the other end.It’s all trial and error, expect to have to repeat it many times until it’s perfect, then spin the wheel and find you’ve set it up on the bent part(there will usually be one)of the rotor, and start all over again once you’ve straightened it.