Quick Tips: How to improve your scales! With Dominic Cheli

I have seen reports that improving scale performance (speed and evenness) in one hand will have a similar effect on the other hand. (Perhaps this partly explains the usefulness of contrary motion practice?)  Do you have any experience relevant to this?  

I ask because an injury to my right thumb (an impact injury, not overuse) is resistant to healing, and I am wondering whether left-hand practice can at least partially replace right-hand practice for scales.  

I understand that this is about improving your scales, but do you have a preferred order or way of learning/teaching scales the first time around? I'm sure there are several approaches, but are there advantages/disadvantages to consider? (i.e. learning all with same fingering together vs. going around the circle of fifths vs. learning major and relative minor at same time, etc....)

I was wondering whether scales should be primarily in our mental memory or physical memory or both?

Thank you for this wonderful lesson, Dominic!