Great to hear things are working out for the better for you and the Furbies. By the time you get the M -T-G in your hands the cats episode with the ringworm should almost be over. I assume the liver is still okay after the treatment with the Ketoconazole, or did you give them some Milk Thistle to help them along through the treatment?
Did you continue with the colloidal silver at 15 ppm, or did you go after the 500 ppm? Myself personally with the experience I've had with colloidal silver I prefer to stay with the lower parts per million normally between 8 and 10 ppm. I add a small amount to the raw food when I making it for a safety factor. Works great for cuts and burns, and it makes a great eyewash as well. What I have found is that it isn't the parts per million that counts, it's the size of the silver particles in the colloidal that does the job that we're after. I can see in the future where people are going to be more interested in the particle size of the silver rather than the parts per million, and will be asking to see lab reports showing the results of the transmission electron microscope (TEM) that will be more to the point. I would have to think that the 15 ppm that you got is a good colloidal silver from a reputable firm, and it could quite well be better than the 500 ppm that you're looking at.