We have created our different guitar and bass models with the combinations we feel would serve you best. High and low are typically good on a bass. A guitar, on the other hand, is often better served by a tone knob. Other knobs depend on what kind of pickups are in the instrument. Each model includes what is needed to match its pickups.
Guitars are fairly consistent on their spacing.
Electric basses have a fairly standard spacing when they have four strings. Typically a bass has its strings a bit closer together when it has five or six strings. This works out fine for normal playing. However, for slapping and popping, more space may be needed near the pickups. We build our basses to accomodate this.