Pinholes are the most common glaze defect in electric firing, and the cause is almost never the glaze. Here's what's actually happening.

Off-gassing, mostly

As your clay heats, it releases gases. If the glaze has already sealed over before the gas escapes, it blows a tiny hole — a pinhole. The fix is a slower ramp, not a new glaze.

Try this

ramp      slow the last 100° before peak
soak      add a 15-minute hold at cone
bisque     fire a cone hotter, so it's cleaner
dust       wash the bisque before glazing

The result

A slower ramp and a hotter bisque clears up most pinholes without touching the recipe. Start there.