Well your on the right track by doing reasearch on this species (and other Amphilophus species) via CJexotics. Jeremy (the owner of the site) is by far the most experienced chancho breeders I've ever known. He was the first to bring this particular species to the states. He was also the first to breed these guys here (long before the Rapps bandwagon).
I recieved my first batch of Chancho about 3 or 3 1/2 years ago. I started with 10 or so and worked my waydown to a single pair. I lost the male some time ago and just a couple months ago lost my female.
Your right about their slow growth rate. They grow slow than any other fish I've ever kept. My female that just passed away was a solid 8" and I recieved her at 1". The male only got to 6" over 2 years before he died. So yes....they grow very slow.
The color of this species has been in my experience is a faded yellow under color with the dark barring. The barring was only present when the fish were stressed or being aggresive. The normal markings weren't bars at all but rather spots. Three to four spots set in the middle of their body the largest being the first spot set in the middle of the body equal distance from the head and tail. Their color (faded yellow) would become more intense when the went agro or the tank parameters were out of whack.
The largest and the main problem with this species in my experience is their aggression! These guys get terribly mean and will attack and kill and other like bodied fish. They don't just target other Amphilophus species (trust me I know

). The only other time I've seen more aggresion from this fish is when I tried to breed them. The male almost killed my female over night. They will need a strong divider if you hope to breed them.
I've never done anything special for the chancho or any of the other new midas type species since I've owned them. Basic tap water and routine water changes. My water is very hard and the PH is very high too, something like 7.8 I think. Temp was basic too, 76-78 degrees.
From my experience they prefer a flat surface to breed rather than the cave or clay pot approach. That's was just my fish I can't really back that one up with any actual facts or research.
Well I hope that helped, they are great fish and you won't regret getting some. If you invest the time they really do get stunning as they grow.
Here is a couple pictures of my female.....