I bought 4 panels of the +S a few weeks back but have done nothing with it yet. My gun plumber (he refuses the gunsmith moniker) is versed in grip making and agreed to mentor me somewhat through the process. I am not very knowlegable when it comes to real ivory but he says it is the best "replica" he has seen.
From the above website: scroll down to the second picture that has grips outlined on the panels. Click on the picture. That will take you to images of guns that have grips made of this material. I believe those guns to belong to cowboy shootist Tame Bill from images I saw on another website.
The grips in the pictures appear much whiter than either the panels from the website or the the ones that I have. The white may be bright photo lighting.
I am not a gripmaker but it is something I have wanted to try on a very limited basis. I have made up several slabs of urethane resin to practice with. I expect a long process.
I know this is not a definitive answer but hopefully is of some help. If you do decide to order you may want to first call the company and check on their return policy.