Hello everybody.  I read the forums for sewing machines but I didn't find the answer to my question exactly.  I'm working with a hat maker here in Italy to produce felt derby style hats for juggling.  We use two layers of 160 gram felt sewn together to weight them properly for juggling.  Thus it's about 1 cm of thick felt that needs to be sewn. The machine they have isn't made for such thickness.  What machines would you recommend for such a job? Is it possible to modify the machines to allow more space?  ( I apologize if I do not know the correct terminology. I am a juggler and I have never sewed anything other than a button) Thanks in advance! I added a picture if that helps.

Here's a video of us hat juggling.  These are not my hats.  I started getting hats made because the ones on the market for juggling I find ugly. 

https://www.youtube.com/watch?v=GO1BJUxAet8&t=48s