I bought my grips from Ahrends, and specified unfinished. I also like them thin, so I re profiled them with 60 grit sand paper. Just keep an eye on the screw so it won't "stand proud". I think shorter screws are available. I also changed the finger groves. More rounded and shallower. That is, I rounded off the points. Then, use finer grit to suit, followed by a Tung Oil finish. I also have reworked Altamont grips, since Ahrends are no longer available.
When sanding, be careful not to make the width less. Stay away from the edges, otherwise, the grip frame will be too wide.
I have also cut grips down to boot grips, I prefer my pinky finger under the grip, so all of my grips are "boot". The only way to get less grip would to go the James Bond route, and use "skeleton grips" Maybe just two turns of duct tape around the grip frame!
73,
Rick