I would have never guessed that your hands were that large from the photos.... you must be a short fella! 
If the handle is comfortable for you on the knife you are already using I would maintain that handle size and just scale down the blade profile(maybe this is what you have already done, I do not know). An actual knife or roughed out handle is always better for comparison than a cut out. I am bad about not doing this too, but it only takes a few minutes to rough out a handle shape in pine to see if it fits as it should.
Chris
If the handle is comfortable for you on the knife you are already using I would maintain that handle size and just scale down the blade profile(maybe this is what you have already done, I do not know). An actual knife or roughed out handle is always better for comparison than a cut out. I am bad about not doing this too, but it only takes a few minutes to rough out a handle shape in pine to see if it fits as it should.
Chris