We're in the assertion of autonomy with ferocity ring with you. Unless he's peaked, DS3.5 responds well to earning and maintaining his freedom (to make choices to e.g. do, wear, go, eat what he wants within reason) by exhibiting responsibility and care, and making good choices. It's a nice celebration when he yells "Yay Freedom!" He also responds well to explanations for negatives. I try to think of it like giving him a blank card, he's going to try to fill it up. I hope that providing him with the reasons for decisions will help him to develop greater appreciation (and doing so helps me stick whatever the decision is - regardless of how loud or persistent the rebuttal). If I give a wiggle, he'll take a wiggle or two.
With you in mind for the ride GHS.