This correspondence reminds me of unreadable dials I have encountered and wondered about, though on a far smaller scale. For example SRNO 1958 at Weston, Notts, is a nice horizontal of 1694, but it is mounted on a pillar in the churchyard (not near the church) at a height of nearly 6 feet, and who could use that to set their clocks or watches? And a well delineated reclining horizontal on the interior sill of a south window in Holy Trinity Dartford, Kent, is 7 feet above the floor! This one is admittedly a memorial, but it still seems odd to put it where you can only read it with a step ladder.
I suppose we have to accept that sundials have often been seen as a "feature" rather than things useful in their own right. -
