Sorry to hear about your printing problems. I too am a painter and I've had prints made on an Epson 9800. Original watercolors with prints on 'watercolor paper' and the prints were so close to the original it was exceedingly difficult to tell which was the print and which was the original painting. So, you have a fine printer, (in fact, the thoughts of actually owning one tend to make me drool!), but as others have said, your settings are way off.
You say you're following Ian's directions, but sorry, you're not. Ian shows quite a few images that are perhaps default settings, not desired settings, then, if you read carefully, he tells you how to change them, perhaps one way in one situation, or a different way in a different situation.
For example, this is the setting Ian uses:
Here is yours:
Note that for 'Working RGB' Ian is using "Pro Photo RGB." Pro Photo is a very large color space. You have chosen sRGB, a very small color space. That single difference is huge.
Also, as for turning OFF RGB. Note that while Ian does show a pic of it off, he goes on to say it's verrrrrry bad policy, as Jeff also says.
You can't just look at the pictures on Ian's site. You have to read the text, then choose your settings.
You've said you have chosen Adobe 1998 as your printer's color space. This setting is there to tell your computer/printer communication what specific and particular printer/PAPER combination you are using. That is, the printer's paper profile. Glossy, matte, pearl, whatever. The amount of ink the printer sprays on the paper will differ radically depending on how absorbent (or not) the paper is.
Ian's printer profile setting is where he is telling his computer/printer that he is using a Premium Gloss paper, a specific Epson paper profile, with an Epson printer.
There is no 'Adobe RGB' Epson paper. Adobe RGB is a color space profile, perhaps a monitor profile, but it is not a paper profile.
Perhaps I missed it, but I didn't notice how you are getting the images of your paintings. Are you photographing them? If so, I recommend you set your camera's color space to the largest you can, so your camera can capture more colors, giving you more digital information to work with. My camera's largest color space happens to be Adobe RGB.
I use Adobe RGB as my RGB working space in Photoshop, but since I've recently bought a wide color gamut monitor, which shows a wider color space than even NTSC, (a very wide color space), I may switch to Pro Photo space for my working space. I'd encourage you to set your camera and your working space to the largest color space you can.
If you are scanning your paintings, it would be a great help if your scanner is also profiled. That is, your scanner's specific shade of red needs to be able to be communicated to your monitor, so the monitor can show it, and to your printer, so your printer can print it. There are monitor, camera, scanner, printer paper colorimeters/and/or spectrophotometers out there. Which one you need depends on your particular combination of equipment.
So, I'd advise you to read, read, read Ian's Color Management article very carefully and follow his actual lead as closely as possible. (You might wish to use Perceptual for black, instead of Relative, though. Try both to see which works best for you. It could vary depending on your specific equipment.)
Also, for what it's worth, I agree with the others, Jeff isn't trying to take advantage of you by suggesting you watch his video. He said he didn't have time (or patience maybe?) to spell things out, I'm sure he was sincere. Jeff, Ian, Andrew Rodney, Chris Murphy, Fred Bunting... and others, I'm sure, are the Color Management Gods (Bruce Fraser, now with the Gods) and they do know what they're talking about, but that doesn't mean it is always easy for us mere mortals to follow.
Good luck with your printer!