You use the same filler for both the 36- and 44-inch sleeves.
Using the pre-drilled holes, attach the fillers. For a 36-inch post sleeve, attach the fillers in the downward direction.
To install a 44-inch Sleeve, simply attach the fillers in the upward direction.
We have an installation video on this page that will walk you through the process - https://upsidebycolorguard.com/patriot-post-mount-installation/