‘Bypass’ setting of princess cut diamond

My boyfriend and I are creating a custom design for the engagement ring and the wedding bands.
The engagement ring will center around a princess cut diamond at a 45degree angle held only on 2 sides (what I’m calling a bypass or half bezelchannel setting…but NOT tension mounted!)
If we want the diamond to (continue) to look very square, is it better to place the bars (which hold the diamond) along the longer or shorter side?
Could the setting serve to cover up some of the diamond edge and appear to shorten the longer side or
will the setting elongate the side/edge which is next to the metal bar mounting?

The answer to this question will help us decide between 2 very comparable stones….one being more square but a bit less in size and color than the other.