How do i adjust overflow height? Ebb & flow

I am using this - http://www.plantlightinghydroponics.com/ebb-flow-float-table-fitting-kit-p-1651.html Anyone know how you adjust the overflow height with that fitting?

on the overfill fitting, there is a 1" piece just below the screen. You can take this piece off to lower height, or add another 1" piece to flood higher.

the pvc? i can pull the pvc off the top part but it seems stuck in the bottom... it'd be easier if i could remove the pvc and just put a different piece thats the size i need but i dont want to break it trying to pull it out if its attached.

botanicare make adjustable fittings. I'm sure there are other brands, too. You stack up 1" risers and then put the screen piece at the desired height.

I dont know that you can adjust the fittings you have right now. Check online or your local hydro shop for some adjustable ones.
Also make sure to get an overflow piece with a 3/4" outlet.