We can feel blessed if our overall body height and the length of our legs works with the standard organ bench as it comes from the factory, i.e. when a plumb line dropped from the center of the top of the bench to the middle E key on the pedalboard measures exactly 20.5 inches [See blog, American Guild Of Organists, Part II].
However if the organist is 6 feet tall or more, even if their legs are short, a bench like this is often too low.
Ideally, every organ bench should be adjustable to the exact, individual needs of every performer.
When the bench is too low there are a number of options:
The most obvious fix is to raise the bench on each end with wooden blocks or shims of the right height; the thickness of these must be decided upon by trial and error until the feet of the organist are resting over the pedal keys where they should.
Wooden blocks for raising the bench height are available from several different companies (Allen, Johannus, Rodgers, are among them), or they can be custom made by any good woodworking technician.
Another fix is to retrofit the bench, or completely rebuild it, with a crank mechanism in its top which allows the performer to adjust the height of the bench plus or minus 2 inches from the standard [See blog, What About Bench Position].
As a temporary fix, until the bench can be raised or a crank mechanism provided for it. the performer can always "throw in the towel ... a cotton or terrycloth towel folded over several times raises the body and allows for some swivel without interfering to any appreciable extent with pedal technique, the knees separating, and the feet reaching the extreme edges of the pedalboard.
Again, if we use a towel this is a temporary diagnostic tool, and we need to check our pedal playing carefully so that it raises us just high enough without raising us too high; there will be a difference in how we're able to play the pedals when the bench is exactly the correct height for us, and we'll notice this difference just like someone who moves from the piano to the organ will notice a difference in the width of the keys.
This was described in a previous posting [See blog, What About The Piano, Part IV].
It's very slight, but there's a difference, and it's something we notice when we're playing.