It is pretty much identical to the example you have shown in the linked thread. I haven't tried it out in UE4/Unity yet, only Substance and Toolbag. Did you harden the seam in the middle on the cylinder or no need?
No, seams across continuous surfaces/smoothing groups should not be hardened. As you can see from that thread there is no issue in UE4, it is an SP rendering issue. Also note that this was just an example to illustrate the issue. I wouldn't put a uv seam there on an actual asset unless it was an extremely long island.