Sue, I know Doc will have the right answer, but IMO, if you want to truly experience the difference in HB soil compared to your usual soil, I'd stick with the kit as designed ... at least once. More perlite means less minerals and probably throws a small wrench in the kit formulation.
I wouldn't be eliminating the minerals, just amping up the aeration to more easily facilitate wicking. What say you Doc?
Yeah Major, I realize that may throw off the mix ratios for HB purposes.