Those sites would give me NIL or results that made no sense, no matter what I typed - even the direct EPSG code.
I then found this hidden gem: http://georepository.com/home.html
From the site:
"GeoRepository is a powerful web application and tool for searching and displaying geodetic parameters from a range of data sources and authorities. The underlying database is based on an extendible version of the EPSG dataset and is kept up to date with each EPSG release. All parameters available in the GeoRepository (including custom user records) can be used in geodetic calculations with a high precision Geodetic Calculator."
I think this site was geared towards a commercial server type product, but the registry is now online and available for public use.
It was so much easier to search with this site and it gave me relevant results.
It is easy to even search by map location (lat/lon).