Like you I have fat fingers too and have tried many of the others, problem on some if it fits over the tip of your finger it falls off easier and the stick on ones just didn't work for me. Came across the open sided thimble and found a winner. It's adjustable, doesn't fall off and give me the right amount of room for my fat finger. Here's a link at Connecting Threads:
http://www.connectingthreads.com/too...eThimbles.html