The pedals are in that order because it facilitates the most common modulations: by fifths, fourths, whole steps, and to the relative minor. Say you’re in the key of C, and want to get into the key of G a fifth away – just move the F pedal. To get from C to F, a fourth away, just move the B pedal. Modulating by a whole step is where the genius of the pedal arrangement is revealed. Say you’re in F, and need to modulate a whole step to Eb – the B pedal is already in flat, so all you need to do is cross pedal on E, for which you have plenty of room because your right foot is over on the A pedal, and move both pedals into flats. If you experiment, you’ll see that most of the whole step modulations will involve moving pedals in pairs on opposite sides of the harp (B & E, C & F). Bear in mind that this layout was established by the single action harp makers in the 18th century, and has worked well from that day to this!

Thank God that got standardized! If only there was a standard string spacing!!

As I recall, it had something to do with Christopher Columbus and food. 🙂

The first two flats are the closest to you. The first two sharps are the next closest. It turns out quite symmetrical for most key signatures, dividing the work between the left and right feet.

Lever harps do not have a standard spacing although many luthiers like to use “concert harp spacing” i.e. conform to the pedal world. That too is a bit hard to pin down exactly. The reasons have to do with the individual diameters and in the case of lever harps with the tension; which differ among individual designs, especially in the bass. For a quick example picture a lightly strung lever harp with thick bass strings -nylon wrap over nylon core. If they were spaced at the same amount center to center as in a higher register it would be very easy for them to hit the adjacent string.