Depends.
Str heroes does not need agi much. So they can just jump str all the way.
But for heroes like Ichigo, str and agi will help.
Str to keep u alive while in Bankai+Vizard mode in the beginning, and agi for super dmg.
+100tome is also less waste of time, 1 click and you get +100 to everything.
Slowly buying other tomes would be a waste of time, remember that other people are farming for money too!