Well, I use a sealing jutsu to seal the items up first and then I can just releas them on a whim. Or, I can gift the scrolls with special conditions and patterns that will make them unseal by themselves. I've been doing this for about ten years so I'm able to adjust it to most things, but, now I normally just stick to using melee weapons while flinging long range things. If I get pressed enough, I might opt for summoning them all at once. [ Which hurts. Just imagine it, Chun Li. ]