Hi chrisb,
I hate to mess up the plans of my trees especially in their young age.
What is the risk : the cut end may start to rot because of inside house air being too ... dry or humid or ...
So question one : is that your only JH Adriatic ? IF yes, I wouldn't try to upset it and would let it grow - just stake the longer stem . You can stake it to the upward direction or to a flat position to slow it a bit. Or you can stake it to a 45° angle (fan espalier style), which has my preference . Later, at summer time, when the tree is outside, you can cut back at 6 or 8 leaves and use the cutting to root it. During that time, the tree will use the additional leaves to build more energy reserves, and the stem will be stronger .
If you have several JHA, I would think a bit more and may perhaps, who knows, try and pinch just the tip and let the smaller leaves develop, and try to get more branching.
Some have a saying that goes : "Are you trying to fetch the egg from the chicken ?... before it lays it" ... So I wouldn't rush on the pinching... But that's just me .