Hi Mark,
I'm no expert on coating, but given that it seems these mesh you are talking about are 83 mesh, I'm assuming you're not printing any detail.
With that, emulsion coating and as it pertains to layers or half layers are not that important (on these very low mesh counts).
I've seem people coat with thick and thin applications on their stroke of a single layer causing very thick area and very thin areas (on low mesh) and it's not made an impact on the image. The coating looks bad visually, but not a bad print result.
As for the water streaks, (did you only have that one coat), or did you do several coats over top? If multiple coats, I'd not be concerned. Either way, I would assume it's a non issue. Maybe an issue of breakdown, if you had a 5000 piece order, but not for low quantities.