I am just about to start making a heat tile for my Coastal. Would MDF board work for this application, size about 300mm x 300mm. I'm thinking of a piece about 16mm thick and routed to accept the heat cord and glue a matching size tile over the MDF. Not too sure what length heat cord yet, maybe 2 - 3 metre with spacings about every 10cm and 15 watt power. Is this spacing too wide for even heat distribution? I intend to mount the heat tile about half way between top and bottom of an enclosure I am building at the same time. No great rush to get this done yet as my Coastal is still under 12 months old and living in a plastic container quite happily for now. What do the experienced members here say?