Always use natural fibre Woollen Felts .http://www.hardy-hanson.co.uk will supply 1 mt x 1 mt in a roll. I bought 5mm Medium density (0.22)felt which I think is a bit soft. I am going to buy 5mm Extra firm (0.40) next time.
I use a mix of 10%Beeswax ,10% paraffin wax and 80%tallow in the winter and 30% beeswax, 30% paraffin wax and 40% tallow in the summer.