First time playing ToS

Gamecube playthrough. I like to optimize my playing experience from the beginning and I don't play too many games like this. So far I have been annoyed with the fact that I have to make a character the main party leader if I'm to reassign Tech (hopefully I'm missing an easier way)

Also, I have 6 available slots for assigning tech - should I just fill them all up with what I think are by best ones in no order and the AI will utilize them all. Should I remove weak ones and use 4 instead for stronger averages?

Genis has stalagmite, its font is purple and I can't apply it. Using t type magical which is supposed to be applicable and I haven't learned a move to cancel it out I don't think.

I am sorry to ask so many questions but the start of these games are overwhelming and hopefully I can get some things answered here from you professionals instead of myself doing further research lol thank you