Looking specifically at a Moody 425 (1980's) there are two keel
configurations available: a standard fin keel at 1.88 m draft and a
shoal keel at 1.44 m draft which has a flared lower edge (foot?).

Apart from the obvious advantage of less draft in shallow waters can
anybody comment on how the different keels perform during different
points of sailing and in different wave conditions?

If the waters where you sail will allow the deeper keel, just go for
the deeper keel and don't waste your time with any other type.

If your local water is shallow, you could opt for the shoal draft keel
but your keel may well weigh more and your windward performance may
suffer as a result of increased leeway and your yacht may be less
stiff, meaning you will have to reef at slightly lower windspeeds.

A question you could ask yourself is: is the slightly improved
stiffness & performance worth 22cm of extra draft, or can you live with
less performance for a shallower mooring/marina berth/sailing at the
top of your harbour?

Artie