I love you for actually having info on what your back injury is. that is good to know so knowing that. . .
the primary healing phase of your herniated disk has long sense been over. In other words, you should (not Dr. Feigenbaum here) be able to lift without it impacting you severely. From my understanding, the best thing you can do to alleviate the long term symptoms of a disc herniation is to strengthen the support musculature of the spine. Basically what these means is watch your form and don't do the same shit that caused it in the first place. Your use of caution is beyond warranted and that's totally chill.
I also love you for clearly taking the cues into consideration. Much progress. A bit of weight shifting around as you get used to the new form is totally fine. If you find yourself going on the balls of your foot don't hesitate to think 'heels'. Keep your knees solid. Set them earlier and hold them there. Your knees should not move in the second half of the descent. Also, if you notice at the bottom that you are obtaining depth by sacrificing tightness. Stay tight and cut out the bottom inch of your squat. If this results in a