The best height slider is this one https://modthesims.info/showthread.php?t=571799&goto=lastpost#post5646929&
originally done by Sammy the Sim and updated by Ted. You will have to look through the comments section to find the Ted update. This slider works as a script. So it goes like this:
add_slider height 20
add slider height -20
You can use any number between 0 to 100. 0 is the default height up to 100. Use the - sign to decrease the height down to 100. This is the only slider that works for children as well as the other ages.