Awesome! I'm planning on building one for my Akorn this winter. Plan on doing the exact same except I was going to use Hardie Board to support the cooker, and then build a wood top with a small gap but the felt seems like a great idea. Let us know how it holds up to the heat. If it works, this would definitely be simpler.
Michael Bard - Char-Griller Akorn Cooker -Custom offset/reverse smoker - Traeger Lil' Tex Elite