1)Have ramza at least lvl 45 i recommend anywhere between 50 and 70(i was 74).

(3)Make sure your party for Velius is all chemist except for ramza(who should be lvl 50 knight with above abilities).

(4)Make sure all of your party besides ramza has mythril guns and auto potion.

(5)For Weigraf you can attack from the side.(when staying back throw Yaguu Drknesses and balls at him)

(6)For velius have all chemists shoot at him and heal if needed(with auto potion it should'nt even be needed),and have Ramza attack him with two-swords.

NOTE:it'll be useful to equip everyone with reflect rings as well