Howdy, new guy visiting - spacer materials?

[Woodcutter]

First off, hello all! I ran across this forum looking for alternative handle spacer materials. I bought a very nice knife, a TOPs model, which came with spacers - about.03" thick. The design of the handle is generally fine but a bit on the narrow/thin side for my hand, so I've been considering replacing the scales with thicker micarta slabs, OR a simpler alternative - just replacing the spacers with thicker material.
Anybody have any recommendations? The original spacers are red, which is nice, but I'm open to other options. Since the scales that are on it now are black I'd probably prefer a contrasting material, but it's not critical. I'd want spacers at least .06", probably more like .09" thick. I'm thinking probably something like plastic container material, or other repurposed material. Possible even epoxy impregnated leather, or maybe that reddish brown reinforced gasket material. but I'd sure welcome recommendations from folks with some experience.
Thanks in advance!