There's actually no best. It all depends on your goal. As for me, I use 3 S Ropes on my 3 ninjas and 1 S Gourd on my MC.

Each tool serves different stats purpose.

Therefore there is really no "best tool set".

Some players set their tools according to their ninjas' mood to max their potential.

Rope is basic overall you don't have to constantly check and change your items when you switch ninjas.

What they said above me is right .. It depends on your needs too, like you've said, you're running a Full-Blitz Team so i think, you must get Shichiseiken since it's main attributes are Attack and Critical, or get Leaf Fan that has main attributes of Ninjutsu and Critical .. In my case, i always using WaterMain and FireMain, that's why my primary choice of tools are Golden Rope for my 3 ninjas and Gourd for my Main .. I'm planning to get a Leaf Fan now for my FireMain and Barrier Ninja for the Nine Tails Invasion and Group's Summon Capture and Shichiseiken for Iruka, AsumaWB ..