If by "dry periods" you are referring to the winter rest period that some orchids, like Dendrobiums, need in order to re-bloom, you need to pay close attention to the pseudo-bulbs/canes to make sure they are not starting to shrivel, which would indicate they are too dry. "Reestablishing" LECA is just a matter of adding more water. I generally just mist the LECA during the rest period with a minimal amount of water in the reservoir. However I also maintain 50-60% humidity as well.
In nature, even though the monsoon season is over, orchids still receive moisture via fog and dew so "dry" is a relative term. It would be more accurate to think of it as a "not-so-wet" period. Dew sounds minimal compared to monsoon, but as far as the roots are concerned, they are both 100% moisture, just for different durations.
Since this sounds like a new adventure for you, better to err on the side of a slightly wetter environment than running the risk of dessicating the roots and killing the orchid. The orchid might not re-bloom, or it could send out keikis, but it will still be alive for another try next "season". The first artificially induced winter is the toughest, after that it gets easier