Hi there! Yes, use Naruto[Sage Mode] as your damage dealer while your Roshi charging his +Ninjutsu boost for his Burning Ocean, you may put Roshi in front and take all the beatings, but you must support him well so he will not die before you get the devastating power of his Mystery Skill, if you put him in back, they you're missing his Full Potential to make you victorious in battles .. If you want to * with that ninjas you have then better to make your formation like this :

X - X - X

Sailor - X - Roshi

Earth - NarutoSM - NarutoSMClone