Just to add a minor detail to the very detailed post bu John T. above.
If the low speed V2 is being constrained by Vmca then it should be as near perfectly constant as your charts will permit, because it is being directly limited by 1.1Vmca.
if you are, instead, Vmcg limited at light weight then you should have the unexpected effect of decreasing V2 with increasing weight. This is because it is V1 which is being constrained by the Vmcg limit, and the V1-V2 difference or "speed spread" will actually be greater at lighter weights, due to the increased acceleration at those lighter weights.
As an aside, I've seen charts where V2 at min TOW was actually higher than at max TOW. That is most decidedly NOT a good thing, but it's theoretically possible if you follow the regs.
So if you look at your V2 data in detail you may e able to determine whether you are Vmca or Vmcg limited at light weight.