I'm new to Step Up Transformers

The Zestos model I have is the PS-1 (bottom photo).  

I believe I ended up at 800 ohms (at least for now) and that setting gave a nice airy high end without it getting thin. 

If you have an 800 ohm loading option on the back panel then you probably have the upgraded version Zestro Andros 1.2

"Id say wait through 2-3 listening sessions at least one hour each in length, before making any judgement of a new cartridge, and that’s only if you’re very familiar on a long term basis with the phono stage. And even then, cartridges do change over time from new, probably more so than any other piece of gear."

Yes!  This excellent advice is worth repeating for emphasis.  Thanks lewm, well said.

My mistake - I definitely have the PS-1.  The setting I settled on was 200 ohm I believe.   

My mistake - I definitely have the PS-1.  The setting I settled on was 200 ohm I believe.   

That's way too low. I would suggest trying at least 400 and check your set up - recheck your VTA, tracking weight etc . The Paua is a very smooth sound, slightly warmer than the more expensive soundsmith's due to the aluminium cantilever. It should not be sounding bright and thin at either 400 or 1000.

Have you tried the two gain settings on the MC input ?

Have the SS Paua and Hyperion MR cartridges.  SS recommends on a loading above 470 ohms and states that below this level upper frequencies will be rolled off.  My phono is adjustable between 25 ohms and 1750 ohms in 25 ohm increments.  After my Paua was rebuilt a year ago it took a while for it to settle (about 15 hours at least) and initially was not happy with the minimal loading settings above 470 provides.  Ultimately, after a little experimentation and a lot of listening, it now performs best at 725 ohms in my system.  My Hyperion MR loads best at 525 ohms.