Jingle Call Addresses

Ok so now that I am back from Mexico I have come back to some of these issues a bit fresher, I think I was getting a bit too consumed by thinking and rethinking this process that I lost a bit of what I was trying to achieve in the first place.

So in my original post I spoke about Call Addresses so lets focus on just this part first.

After speaking to Peter Saint-Andre, the Reachability JEP was introduced to me. This JEP seems quite useful for our problem, but now raises a few more questions.

Here is my question to the community:
If a client supports IAX directly, and you need to discover what extension to call him on whether its "555" and you are logged into a PBX (Asterisk) do you:

1. Query for reachability, which might respond with an extension of "555" and you simply dial this extension.
2. You use Jingle IAX which the extension is added in the candidates. (Jingle currently only supports IPs)

#2 is where I was focusing on prior to learning of Reachability. So which way is proper? Part of me wants to say Jingle from my previous thoughts, and extending Jingle to support more than IP end points.