I do not believe that gloves are all that important for hiding. I just do not think a turkey is going to see my hands and run for the hills...
But, in running a box call, I do feel that gloves are important, cause it stops the sweat and oil from getting on the call. More important than chalk is preventing that sweat and oil from your own hands on getting on to the call.
I always keep a baggie with a couple paper towels in my bag in case I do get water, sweat, or oil on the call. Wipe down the call and re-chalk...
I do not believe you can put on too much chalk, and if you do, using the call should solve that problem in short order...