Having the Key Blade Solomon Weapon for every element will greatly help with the lower floors and beating them quickly without the need for many or any Kami. You only need 1 copy of it, no need to MLB.

One of the early strategies that I read from DMM for tower was to hit the early floors on day 4, then wait 3 days for all your teams to CD, then proceed to the higher floors. with your strong teams on the last day... It was something like that. I don't remember all of the specifics.