I've been trying to get my hands on some of the new plastic grips to trim up my Match for awhile now. The other day I found a company that sells a composite grip for the Witness, https://coppergungrips.com/. They purchase page took me to gunbroker a little odd but I've bought enough to be comfortable with broker. So $34 dollars and 5 days later they're here. Mine took a little trimming to fit to my liking, they trim easy enough and come in a lava rock or grip tape texture, 10 colors. Any way heres the nuts and bolts of it I measured the width of my old rubber and new plastic ones at 4 spots. Now I like they feel of these shape wise and they are considerably thinner.
Rubber Copper gun grips
1.397 1.201
1.383 1.248
1.385 1.288
1.387 1.318
Now none af these numbers can be exact and their is more to grip feel than width alone, But you can shape plastic much easier than rubber and they're priced to experiment. Anyway heres the pictures the blue lines are where i measured at with calipers.
I am not a paid anything, Just thought someone else might have been searching for thin plastic grips also, This site has helped me numerous times just looking to try and give back a little