Well, if you take the Medrash litterally, his ankle was 30 Amos high. MOSHE rabbeinu was ten Amos tall, his stick was ten Amos, and he jumped ten Amos to hit his ankle. An ankle is usually around a Tephach from the soul. A person is considered three Amos tall, not including the head, so the ankle is an 18th of the height. That would put his shoulders at 540 Amos high.
The only problem is, being that he wasn’t quiet built to normal proportions, we can’t really tell if his ankle was higher relatively, or lower, than other humans. It would seem that he was way more muscular than his height would account for, since he was able to lift a mountain.
The Torah says that his bed was 9 Amos wide. It uses the term Arisa which some say means his crib. So, a normal person’s bed is three times longer than its width. A normal person’s bed is like four or more times the length/width of a bassinette. That means, his bed as an adult should have been at least 85 Amos.