Unless you know for sure that the Opus you're considering is black, it's not necessarily so. Emerald has produced a number of Opus models in their range of colors. Also, the tuners used on the Opus may be different than those used on an Artisan, and there may or may not be electronics. If the one you're looking at does have electronics, older ones likely have the barn door b-band, whereas newer ones likely have a Baggs system with soundhole controls.

Yes pictures are black. Color confirmed. The K&K mini has been professionally installed I am told. I wonder about that though. Emerald told me that if I ordered a guitar from them that I would need to specify that I wanted to install the K&K because the would need to make sure that the surface under the bridge plate was perfectly smooth for best contact .

True about the k&k. If Emerald installed it, or the buyer asked Emerald to prep for later installation, it would've been done right. If no such instruction was given to Emerald and the owner later prepped and installed, I have no idea what issues there can be (maybe poor adhesion, separation, rattling). The seller should be able to tell you who prepped and if not Emerald, you may want to inquire with Sean at Emerald about it, especially to determine how you can do it yourself. I hope it all works out in your favor.

What exactly happened to the guitar? Was it high humidity itself or too much variability in the humidity?

I'll agree with Captain Jim on this one. I have three CF guitars now (no Emeralds, however) and don't intend to buy another wooden one in this lifetime. But there is one all-koa Taylor 424 that is just too pretty and sounds so good, so it will remain with me for life. But all the other wood guitars are slowly drifting away. Low maintenance and worry-free is.... freeing.

It isn't inexpensive, but I found that the Blackbird El Capitan is very Taylor-like in its tone, and really looks like wood too.

My house regularly gets into the 35% RH range, and I don't have any problems. When it gets lower than that (like right now at 8°F with heavy heating) I use in-case humidifiers. Living on a boat should not over-dry your wood guitars, even without OCD levels of humidity care. As Jim said, if you are comfortable, the guitar probably is too.

I used to live in Alaska where winter indoor RH was hard to keep up to 20% and humidifying was mandatory for wood instrument survival. That is how I got into CF guitars in the first place. But in the summer and on boats, there were never any problems with the woodies.

I am told this was bought new from Mac Nichol guitars and Michael Stone of same prepared and installed the K&K. Also a mother of pear saddle? To enhance the tone? Never heard of a mother of pearl saddle

The fact that Michael set-up that guitar with the k&k, and installed the mop saddle which a number of members here recall he did to enhance tone, then you have absolutely nothing to worry about.

I agree with Tom.

I had the pleasure of meeting Michael Stone and watched him work on one of my guitars.

He is extremely knowledgeable and meticulous about the quality of his work.

I wouldn't worry about any work he did.

Another small difference between the Opus and the Artisan X20s
the new Opus has Gotoh 381 tuners (16:1 ratio) and
the new Artisan Gotoh 510 tuners (18:1 ratio).

Sorry.. I just noticed different tuners had already been mentioned.

Yeah, I feel you man. It sucks. This is why I tried to keep a limit on the number of guitars I owned :D. Rainsong guitars are not bad, and they are worth the money. However, wood guitars are generally much more special than the non-wood ones.

Michael does good work - if he installed the K&K and set up the guitar, you can be sure it has been done right. Sounds like a good find!

To insure that X20 performs well plugged in, K&K Sound recommends using a pre-amp with a 1 meg ohm input impedance with the K&K mini pure.

I have the K&K in my Martin and I have a red eye preamp. So I have that covered for a demo if needed. Still waiting on call back to try guitar.
Maybe after new years celebration over.

At that price point the X20 is a great deal even without the K&K. If it's still available and you are interested, then you should go for it. You should be able to get your money back later without too much trouble if you change your mind. Have fun.

Help deciding going only carbon fiber
 

Count me in the group who have all CF acoustics. A CA Cargo Raw, a CA OX Raw and really like them both. I may be less discerning but I don't see any more wood acoustics coming here