The available non-metal spacer colors should be red, white, blue, and black. Choosing either one of these as a solid spacer color should be fine, and because there is no metal involved, it should be a non-chargeable option.

My guess is that the finger grips work one way. Specifically that conventional handles can have conventional finger grips of #14 finger grips, but that other handles, such as the Fireman Special, can only have #14 finger grips.