"Best" line - up depends on situation, I can show U most boosted lightening formations but they can become useless against enemy that throwing at U debuffs instead fight with U(for example fire main aka annoying wizard) , I got Fukurokumaru summon with Sasuke Barrier ,Guy boost and Kimimaro as a shield I can kill enemy in 1 combo but Guy is fragile and they are not protected against debuffs so if enemy got 1point more initiative fight ends before its even started... We have advantage in teaming up with sword users (u can be immunue for first two rounds) but even with that first two rounds it will be probably not enough time to break some tough earth main formation or whole time healing water team. So i think "best" doesn't exist for F2P players ,U need whole team of rare monsters to have 1 line up that handling everything like with Pain Tendo etc.