Milk Thistle Dosage for Dog

Hello:
I have been searching the web for information on what is the correct
dosage of milk thistle for a dog, but have found so many differing
values that I've filled two pages in a notebook, front and back.

My dog has developed some liver problems due to the chemotherapy drug
Lomustine given as a precautionary measure after he had a mast cell
tumor removed. His ALT value is very, very high, and while he does not
have any symptoms of liver disease/failure yet, I am very interested in
starting him off on Milk Thistle and perhaps SAMe. Unfortunately,
neither of my vets were interested in helping out when I talked about
either of these items, esp. the MIlk Thistle. My dog's cancer vet
believes that the high ALT will come down after the chemo leaves his
system entirely in a few more weeks, but is still making plans to do a
biopsy (which I would rather not do at this point considering on one
hand he tells me not to worry yet but wait, yet on the other hand hurry
up and do more tests and a biopsy even though he had a very healthy
liver before chemo treatments).

ANYWAY, I am looking for information on Milk Thistle in regards to
correct dosage. I have purchased a "Nature's Answer Milk Thistle Seed
Fluid Extract (Alcohol-Free)", which I was told was the most
concentrated, but have no idea how to dose it correctly for a dog. The
fluid values vs. the dry powder values are very different for amounts
that need taken.

Any advice from people out there who have used this would be great.
Thank you!!!