Your brand of IDE should never have any influence on the webapp. For one thing, production webapps are far removed from the IDEs (if any) that produced them.
Locale actually doesn't control the character set encoding, though. Just the choice of resources. For example, messages in Italian would be the preferred return for resource lookups.
What you really need to look at is the Code Page in effect for the web pages themselves. UTF-8 is the most common, and it does have support for European accented Latin characters. However, for an exact match with your PostgreSQL settings, Code Page Windows-1252 would be the preferred setting, since that way the database and view would be using the exact same encoding.
Code Page Windows-1252 is very similar to the ISO-8859-1 Latin Unicode glyphset, with the most notable exception being things like the open and close-quote characters. ISO-8859-1 is actually preferable (even Microsoft recommends it these days). Non-Windows webclients such as Macintosh, Linux, and Android devices will be the most offended, otherwise.
It's unlikely that you can do anything about it at this stage, but it's worth noting that PostgreSQL's default codepage for database creation on Windows-based servers is CP-1252, but on the Unix systems, it's UTF-8.
Customer surveys are for companies who didn't pay proper attention to begin with.