The correct potting and mounting of these plants is perhaps the most critical element for the culture of these species. Rain and morning dew dries quickly. The moisture the plants need is trapped in the spongy, insulated roots and the fleshy leaves. These conditions must be simulated in cultivation. The medium should be open, airy, fast draining and drying.
Cattleya mixes based on bark are often too wet or compacted for adequate drying at the roots.
Logically, a medium based rock or gravel may be considered. Granite, lava or some other rock could be suitable if not too acid or alkaline as it can be from some sources. Hardwood charcoal is good, although some gravel may be used to hold its lightness down. Tree fern fibre arranged vertically has worked well in clay pots for some growers. The best medium for your conditions will have to be experimented with, as will the issue of clay or plastic pots.