I don't have an Enya Nova U, nor any Enya, so i have nothing to say about that. But I read your post and wanna share.
- If the stock strings sound OK to you, then it should be fine?. People like what they like. But ultimately, the one person listening to our playing the most is ourselves, so maybe it's better to go with what sound OK to us? Also, if you like the feel of the strings in your hands, then that always helps.
When I started playing I listened too much to what better players say about strings and wood and stuff, but the more I play the more i realised that it is OK to like what I like.
- Low G is a nice alternative to high G. I don't think there is a Pro and Con to each. It depends on how you play and what you like. High G sounds great, Low G sounds great. I have a couple ukes strung with low g so I can get a different sound whenever I want to, without having to re-string my uke. I love low G for that bass sound. And it is helpful for me when I do some kind of finger picking. Most people might say that Low G strings are not so good for clawhammer style which is what I like playing, but I like it. It all depends on what you like.
- regarding the different thickness in strings- yes that's a thing to take note if you wanna change your strings. "cause sometimes some strings can be too thick to fit on the grooves of a particular uke's bridge and saddle. But since the Enya set have thinner strings, then that won't be a concern for you.
Another thing I know from my personal experience is this - I have this cheap solid cedar top tenor that sounded sooo lovely to me when it was strung with aquilas. Then I went to put some Low G Worths browns on it, and although it sounds fine with the Low G, I think it sounded better and played better with the original high G.
It is all trial and error and you will know what suits you best, i am sure.
Er, if you ended up not liking a set of strings you have bought, you can use them on another uke. Or give them away as prizes in the Seasons!