I did my last Rossi Thermofits in my oven at 200 degrees for six minutes, then strap in and wear them for 20 mintues. Make sure you padd around the toes or wear cut off socks to make some room for your toes.
There is a video on the web that demosntrates this but I can't find it at the moment. Anyone else have it? I think it was called 'Cooking with Big Tom".