Ghostlander

Alright I really need some help because I'm confused. Since seals are kinda rare right now, i dont wanna use em all up so: (1) Do Master and Second seals become more common later? (after chapter 10?) (2) Which order should I use the seals? I want my avatar to be a dark knight. He's a lvl 18 Tactician. Do I make him a dark mage with second seal and lvl him and then use master seal? Or do I make him grandmaster and get him to 10 and then use second seal? Which is faster? (3) Will I be able to re class/promote most of my favorite characters? It would kinda suck if I could only have like 2-3 classes that were still lvling up and being stronger, etc. (4) Which class changes are most beneficial?

IT says that Gerome can also class up naturally to warrior or hero? Is this correct? And all outside body models clad in blue? Seems kinda...even more generic than generic. Anyone have any images?

Alright, my main question is, When I reclass a character, does their appearance always change? If so, can anyone provide any links to examples of this in images or video? (1) MAINLY, I want to know, because I want to reclass Gerome as a War Monk but, I fear that his black armor would be white robes or something, which would really be wrong with his head and mask. I just wouldnt want dumb looking combinations for the sake of a new class. (2) ALSO, could anyone give me reclassing suggestions? Which units would be better as other classes? (3) OR what class the my unit would fit into best? (4) Also, how do you get to be a dark knight?