Words with 'z' as the first letter that end with 'eco'

In Scrabble, what is the highest possible score you can get using this list of words beginning with 'z' and ending with 'eco'?
As there are only a small amount of words available, you can only play 'zacateco' scoring 21 points.

What's the longest word you can assemble using words that start with 'z' and end with 'eco'?
The longest word is 8 letters, which is 'zacateco'.

In total, how many words could one make using these specific combinations of letters?
From this page of words beginning with 'z' and ending with 'eco', there are 3 entries which are available.