Actually, it is not too readily available here too, but it was just a suggestion, just choose what is there easier to source..at times, it will be perlite.
But when I do find pumice, in one of the nurseries, I get a bag for future use. I have also been experimenting through the years, other ways to make them well draining, have found kanuma and akadama works too, but not easier to get a hand of unless we happen to be in Japantown, SF.
Just got to make that media more well draining, since your Spring to Summer is more rain filled than ours.
