hay,
depends on size of your tank if it can handle 90kg but yes i know lots of people that have a mix problem is they worth about the same price and fiji rock looks much better.
if you do go mixed put indi as base and put fiji on top and put a few fiji on bottom front of the tank to hide the indi imo.
i did that on my last tank before it split due to moving house.
no problem with it at all being mixed.