RE: Signing AWS Requests with Signature Version 4

While I have my SRVPGM working with the sample data (thanks to Chris), I'm not sure I have everything covered just yet.

First question:
AWS4 says this about the "absolute path" (the example doesn't have one)
Normalize URI paths according to RFC 3986. Remove redundant and relative path components. Each path segment must be URI-encoded twice.
Example Canonical URI with encoding
/documents%2520and%2520settings/

I'm assuming this is "documents and settings" because %20 is a space and %25 is a percent sign.
I'm using the SQL encoder (twice) but I'm not getting the same result.
Exec SQL values trim(systools.urlencode(:str1, '')) into :str2;

Maybe I should just us the encoder that's part of HTTPAPI?

Second question:
For the query string, AWS4 say to:
URI-encode each parameter name and value according to the following rules:
Do not URI-encode any of the unreserved characters that RFC 3986 defines: A-Z, a-z, 0-9, hyphen ( - ), underscore ( _ ), period ( . ), and tilde ( ~ ).
Percent-encode all other characters with %XY, where X and Y are hexadecimal characters (0-9 and uppercase A-F). For example, the space character must be encoded as
%20 (not using '+', as some encoding schemes do) and extended UTF-8 characters must be in the form %XY%ZA%BC.
Double-encode any equals ( = ) characters in parameter values.

Not sure what needs done because using the simple example value below (not encoded) works just fine.
Action=ListUsers&Version=2010-05-08

Any thoughts would be appreciated.

Greg