Well, I made them! I ended up getting a container twice the size as the guy's website mentioned (he said a 6 cup container) and, as you can see, they still barely fit.
I used the recipe my friend got from her baby shower:
2 cups warm water
2 Tbsp. baby shampoo
2 Tbsp. baby oil
I did, however, play with the type of oil. I put some tea tree oil and lavender oil in with the baby oil, totalling 2 Tbsp. The towel turned out a little oily so next time I'll probably not put as much and I'm thinking of putting plain mineral oil in it instead of baby oil because Karrots has such sensitive skin and doesn't need the baby scent with the lavender in it.
A hint for anyone who may attempt this: pour the liquid in slow! It will absorb it all, but it does so slowly.