I always negotiate....sometimes we can come to agreement and sometimes not but I get a budget and tell them that is what I have - and respectfully ask if that will it work for them?....that said I am excited that you love Westender as I have my first stay coming up soon.
Try Catcha Falling Star - ask for Andrea and see what she can do - not a bad room on the property.
Xtabi is nice - their pool is gardenside as are most of their rooms but a few on sea side.
Other places on cliffs w/pools are Mirage, Negril Escape and Samsara.
Have you looked at negrilonestop.com - they have a great Cliffs and Beach map that shows properties/amenities/photos and rates.
Good luck - let us know where you land and enJOY your reach.