Question on timeless jewel (Elegant Hubris)

I'm following a build for my first char, and am now getting to the point where I'm trying to get gear that matches up with the late-game portion of the build. The build is using an Elegant Hubris in the passive tree, and I'm just getting around to seeing how it works.

From what I can tell, they're all unique (no pun intended) in that each different Elegant Hubris will change the nodes in the tree differently from any of the others. I assume the # of "coins" referenced in the description determines how this happens.

With all this in mind (assuming I'm correct) how in the world do I decide which one to buy in trade? I won't know how it will affect my tree until I have it, and if it's a dud, now I've wasted that currency. Is there a way to know how the available jewels will affect the tree before buying?

First off, you are correct. Every jewel has different stats that get applied to your passive tree. One thing that is consistant are the names and keystones.
An Elegant Hubris with the text "# coins to commemorate Cadiro" will always provide the "Supreme Decadence" keystone.
https://www.poewiki.net/wiki/Elegant_Hubris

Nowadays we have tools like PoB and https://vilsol.github.io/timeless-jewels/tree that let you figure out the exact stats of a jewel without actually having it. These tools include a link to the trade website.

What a lot of people do is they search for one or two stats they really need and just pick the cheapest option. People rarely go for an ideal or exact jewel.

I've also noticed that your character is level ~68. Timeless jewels are usually something people add very late to their first character at level 85+ because of the jewel's complexity. Make sure that this really is your next upgrade as they can be expensive.

Thanks for the tips about using the external tools to evaluate the jewels.

This is far from my next purchase, as you said, I'm still a little low yet. However, I'm just trying to understand where I'm going long-term with the build. I'm right near the point where I'll convert from the leveling passive tree and reset to the main passive tree. In looking at PoB, of the 720% minion damage available in the build, 1/3 of that (240%) comes from three nodes he gets from the conversion of passives from this jewel. That's a huge chunk to leave to chance, so that's why I'm trying to get an early handle on it.