My 2cents? The Delta 16 isn’t even in the same league as the NDK. To begin with, they aren’t designed with the same design philosophy in mind. NDK boats are Brit-boat based. They are more concerned with performance than stability (though the NDK boats are very stable for Brit-boats). Delta’s are more of a North American design. Higher volume. More stability. The NDK will have much more rocker, muck less volume, and though both boats boast a soft chine, the NDK will be harder than the Delta, all of which means the NDK is much more maneuverable, and I’d argue much more fun. The Delta’s only real advantage will be that it will hold more cargo than the NDK, and will perhaps feel slightly more stable while sitting still.
I also argue that composite boats are more durable than thermoforms, so if you’re planning on playing in very dynamic waters, either go with a traditional plastic or composite boat. I’ve heard from credible eye-witnesses that thermoforms can literally break in half in serious enough waters. I personally have seen thermoform decks crack during re-entry practice.
As for fit, one of the main reasons the NDK you tried out fit so well is because it has a much lower deck than the Delta. You’ll have to seriously pad out the thigh braces in the Delta to get anywhere near the same feel. And, if I’m not mistaken, The Pilgrim has a much narrower cockpit than the Delta 16 which means you’ll need some serious hip padding to come close to the Pilgrim fit as well.
Granted, I’m bias (I own an Explorer and a Romany C), but if I were you, I’d definitely choose the Pilgrim over the Delta. Admittedly though, a lot of the P&H boats already mentioned are good suggestions to try out, as well.