Hi! So like, I'll be riding Max and ask him to canter... But he ALWAYS take his right lead, no matter what... I try to put my inside leg forward and outside leg back to make him take the left lead but he just won't do it! Anyone have any other tips on making Max take the left lead?

Try trotting him in smaller circles to build up his muscles.  It is probably hard for him to take that side.  Ask him to canter to that lead in a smaller circle (size of a round pen or even in a round pen).  If he cross canters, trot him some more, again to build up his muscles.  They all have their "favorite" side they like to canter.

It took me a long time to get Maverick to tuck his head and ride the trot collectly since he like to travel with his head high.  This was OK in endurance, but not in western classes.  I am still trying to build up his muscles to be collect at the canter.  He was right leaded too, but lots of trotting in circles helped him.  I also ride in spurs so that he "hears" me better.  That way I just touch him lightly and he knows what I want.  Actually now, when he feels my outside leg shift back, he will canter.