[DGraham]

Hi! I belive you want to hold down the alt key (option key for Mac I think) and then select your track size. That should apply your selection to all of the tracks. The alt/option key is a general "all" key for a lot of other functions as well. You can also use it to bring all of your faders to unity at the same time for example.

You can also use it across only the tracks you've selected by selecting the tracks you want to affect, then holding shift+atl/option and making your track height selection.