Unless you have a scale that can measure in mg, you will be using your best guess for measurement, aka a sprinkle or hefty sprinkle. I have never found a recommended dosage in hedgehogs, and the best information I can find is a dosage recommendation for dogs and cats. When my vet recommended these items to me, he stated give her a sprinkle.
This post is going to be long, I apologize. Cancer is a topic I am almost constantly researching and reading about. I tend to get a bit long winded when someone asks about it.
In my own research, I have found several recommendations for dosage in dogs. I don't think the vets really know how much to give, so we are left to make our own decisions. I can tell you what I have found though.
I'd like to recommend another amino in addition to the lysine, l-arginine as part of her palliative care. Arginine, it combined with omega 3 has shown to have some great benefits in slowing some cancers down. Discuss adding it with your vet, or do some research on it with the type of cancer your hedgehog has.
If you want to measure out dosage, you can find a milligram scale on Amazon for just under $30. I bought one recently as I like to be consistent in dosage and well, I found some numbers for these items in regards to dog cancer. I was amazed when I measured out the first doses as the sprinkle "measurements" I was using actually were very close to the recommendations I found for dogs.
I did google book searches, searches on the National Medical Publication library, and just general google searches looking at dog/cat forums and various other places to see what people were doing. This is what I have written down.
Arginine - 647 mg/100 kcal of food. Another recommended between 500-3000 mg split 2xs daily for a dog. I guessed that the range was based on sizes of dogs.
Fish Oil - 1500 mg/100 kcal of food. Most say you really cannot give enough fish oil to make up this amount. I give about 5 drops of oil daily to Rose. I puncture a hole in a fish oil capsule and squeeze tiny drops out. Rose is 850 grams so she's a big hedgehog. Start out with a much smaller dose of this as the oil will cause some loose stools initially. I stuck with this amount as it is the amount that doesn't cause loose stool and I have noticed a major improvement in Rose's quill coat & skin. In my researching I have read that salmon oil seems to be the highest in omega 3s and the preferred type. Its a form of omega that the body can more readily use. Flaxseed is ALA omega 3 which the body must convert before using it.
Lysine. This one is difficult. I haven't been able to find much about dosing for cancer, most of the information that comes up is for feline herpes. The one site I found gave the same dosage as the arginine though.
You may also want to add acidolphilus to her diet. Acidolphilus can help aid digestion.
If you find anything different, I'd love to hear it. Rose has been on these since January. Rose was first diagnosed with mast cell cancer in August 2010 and had 2 surgeries to remove 2 tumors. Her 3rd tumor showed up in March and was inoperable. It has grown very slowly though and she is still doing very well. As I mentioned her quill coat & skin look the best they ever have on this stuff. Rose also takes IP6, cartilage supplements & is on a high protein/low carbohydrate diet (ask your vet about this diet change too). Doc has us reducing carbs. There is research out there that shows carbs can feed cancer/aka allow it to grow faster.