I've done that and in the case of all of our WS kayaks, it didn't work. To some extent all 6 Tsunamis leak and both Zs leak. Some are worse than others.
It's just frustrating to see a great product ruined by something so simple to fix.
Even if WS started using the old Dagger covers from 98, they'd be better. My old Magellan leaked much less and I didn't really consider those that dry.
While it is true that NDK is very uneven in its qc and one has to be careful when buying an NDK boat, mostly they hold up to heavy use and abuse very well. I've been in numerous rocks/ledges/etc... classes wherein the majority of boats were Explorers and they survived beautifully.
As far as Valley, while I had a used Nordkapp LV with issues which Valley replaced with a beautiful new boat, my Aquanaut has been used in all those rocks sessions to which I refer and does not even have spider cracking. Of course it is a layup no longer available - ProLite.