@michaeljp
Sorry, been out in a boat today. Just catching up.
To handle a couple of basics - NO NDK boats except maybe a tandem if they ever made one have ever had rudders. Rudders are mostly an American continent and some other manufacturers - like Kayak Sport - thing. Older ones had rope skegs, some people hated the rope skegs and preferred cable/wire skegs, I have both between my boats and don’t have much bad to say about either.
That is not to say you will never see a photo of an NDK boat with an add-on rudder. Kayak Sport made some that could be creatively fit onto a variety of boats, and when you are doing far more serious expedition paddling than most of us it is not uncommon to see a boat fitted out with boath a skeg and rudder. But we are talking about long, often multi-week trips.
As to the two boats you mention - a post above has it right on the Nordkapp HM. It is stiff in the water and you will have to take it over on edge to turn it. As much as new paddlers tend to like boats that track well, they also find themselves stressed if they are out on a windy day and have to argue with the boat to get it to turn home. The Nordkapp HM is also within their full out touring designs - it really does not behave at its best unless it is carrying a decent load. I know one person who had a string of weights that he put into his boat (it wasn’t a Nordie but similar issues) for each paddle to get it down in the water right for day paddling. He was OK with that accommodation, others may not be.
The NordKapp LV turns much more easily and will behave as usual with a day paddle type load. I have my husband’s that I hope to make my local paddling boat this coming season after I have some winter pool time. But that is because I will need to get my roll back on both sides to paddle it. The Nordkapp LV is sweet and slick thru the water, rolls like a dream, but is relatively unfazed by whether it is upright or upside down. The boat is happy all the way thru 360 degrees. New paddlers usually have a strong preference for the upper 120 degrees of that.
But honestly, lack of a day hatch and rudder and all, you may have a score with the Current Designs Solstice GT. Confirm the rudder is working OK but it probably is fine, CD rudder assemblies tend to age well. My first sea kayak was a Squall, a smallish cousin but in the Solstice line. All the Solstice series boats have a general tendency to be relatively fast thru the water and have pretty strong secondary stability. Translation, where the really rolly boats like the Nordkapp LV will keep going when you are off balance, the Solstice boats will stop before capsize. It is a tracker and will require some convincing to turn in a lot of wind, but it has a rudder if you need to punt to that and is not so argumentative about it that you can’t impose your own opinion. The have ridiculous storage capacity for their apparent size, you can load those boats to the gills. It’ll feel like you are paddling a Mac truck, takes a bit to get speed initiated, but it is kind of nice to feel less limited on what you can carry.
What I am saying is that these are great boats to get you on the water and back home again, and when you start out those are fairly important.
I suspect it is actually 17 ft and a few inches, but if you can handle 17 ft you can manage a slight overshoot of that.