I purchased a used 2x8 traditional CDL evaporator late in December last year, but never got around to getting the sugar shack built in time to set it up, so was forced to use the old homemade evaporator for one more season. I'm getting around to bricking and setting up the CDL now and am certainly looking forward to using it this season. In the instructions for setup they recommend using sand or vermiculite to build up the rear after the belly ramp. I know that both are able to absorb moisture, which is capable of shortening the life of the arch, so I wonder if it's even necessary. Has anybody else run this style of evaporator without building up the rear? The flue pan I have has raised flues, so I understand the preference of forcing the fire through the flues, but there are other evaporators out there that don't build up the rear (the Lapierre Vision for one) and just put down a blanket. Thoughts?