Water main on Roshi not really good in this meta since she is easily controlled unless you sacrifice the poison tai and use substitution jutsu to prevent controls which is at 40% chance.

Lightmain, Killer bee, Yagura and Roshi is perfect if you stacked your roshi. Dont rush when using roshi's mystry let him take the hits on round 2 just make sure he wont die and then use it to regain your hp. At least with lightmain you can heal without problems unlike water main you have to look out for the opponents controls and its not guaranteed that you can get your heal off.