I’ve no idea why the Horizon costs more and is seen at the higher spec pedal
Because concavity is better for a pedal. If you can get on OK with the protruding, convex axle then the Electron is probably great but it’s the thing that turns people right off it. The reason the Horizon is fatter is purely to give it shape, you don’t stand on the axle bulge with it.
Like i say, I own both but the electrons got retired to the commuter very quickly. They’re a near miss, for me.
Can you put proper, metal pins in the horizons?
All but the outer pins are metal. It’d be fairly easy to drill them out if you really want to but I’ve not bothered. (might weaken the cage too I suppose)