For a snubber I used a needle valve in the line to the gauge and tightened it down until the needle on my gauge has just a slight movement. This allows pressure to bleed back from the gauge so the needle responds to engine reving. If I open the needle valve 1/2 run from completely closed the gauge needle will bounce like crazy. But your's is electric, meaning it has a sending unit right? Maybe that has snubbing built in?