Why not the S-52EHLA ???
I have one and I like it. It has a single pawl, but the tooth count is fine enough for me. It is very smoooooooooth!
Funny thing...williams web page has the S-53A listed as double pawl and 72 teeth. On amazon someone left a feedback stating it was only single pawl. On ebay all the listing are just pasted from williams page. Then you state single pawl. Hmm
There are other threads on this topic.
Williams updated the mechanism several years ago and never updated the catalog. The new round head Williams ratchets have a single pawl mechanism. The old design was dual pawl, but that isn't made anymore
Edit -
This thread has pics of the new mechanism:
http://www.garagejournal.com/forum/showthread.php?t=192799