wire size

[Brion Toss]

Hello,
Is this a discontinuous rig? That is, do your "uppers" stop at the lower spreaders? Is it a B&R rig? The tune you put on makes sense for a conventional Bermudian rig, but it isn't optimal for disco. Any degree of tune will make your boat sail better, but we need to know the details and the reasons behind them, to get to an optimal tune.
Also, yes, it is usual, and for good reason, to have different wire sizes, as the loads are different at different points in the rig, regardless of type.
Fair leads,
Brion Toss