It's not too complicated, you can use /hsave -n to save all data values in the hash table to a file. After saving use /filter to sort it, /filter -ctffeu 1 10 file file where it sorts the lines numerically (looking at the whole line since chr 10 was specified as the token separator and it cannot exist in a line) in descending order
Now the highest data value is the first line of the file, you can use $hfind to refer back to the data item/s
