Words with 'pf' at the start and 's' at the end

In total, how many words is it possible to make using these particular combinations of letters?
On this page of words that start with 'pf' and end with 's', you have 2 combinations that can be selected.

What's the highest scoring word you can play in Scrabble ?
As there is just a small amount of words available, you can only use the word 'pfennigs' scoring 14 points.

Which word in particular from this list is made up of the highest number of letters?
Consider 'pfeffernuss', which contains 11 characters.