PeopleSoft ASM policy and Max URI Length

Generally keeping your URIs under 2000 characters is considered best practice, so 2048 should be fine. Having said that, RFC7230 says:

Various ad hoc limitations on request-line length are found in practice. It is RECOMMENDED that all HTTP senders and recipients support, at a minimum, request-line lengths of 8000 octets.

Given a standard 8 bit character in utf-8 encoding, that would be 1000 characters.

As a matter of course, if your site is requiring longer URIs and this is not in error, I would find out from the webmaster what the longest URI he would expect is and set the value to that. This is also a good opportunity to find out if this is in fact an error, and if so get it fixed.