Best monitor size for portrait orientation + advice regarding Dell monitors

[cpugeek21]

I'm actually looking around for a new monitor, and after doing some research, I have a couple of questions.

1) is there a "best" size for portrait mode? For instance, a point where it just becomes too long and strains your neck or other disadvantages?

2) is there a big difference between 16:9 and 16:10?

Reason for question 2, is because I only have the budget for one. And the 3 monitors I'm looking at are as follows.

Dell u2415 (24" which has a 16:10 ratio)

Dell u2417h (24" as well; touted to be the best fhd monitor you can get at this price point)

Dell u2717d (27" and qhd, but also much more expensive)

Anyone who has a bit of experience with monitors and can advise me? I'm looking to get a monitor, mainly for productivity. Don't have too much cash to splash on multiple monitors so I'm looking to slowly add one at a time. It's most likely going to be a secondary monitor; i should be going for an ultrawide or 4k primary landscape monitor in the future.

Thanks!

 

[cpugeek21]

MERGED QUESTION
Question from cpugeek21 : "U2415 vs U2417H"

So i'm planning to pick up either one but I can't make up my mind.

I'm interested in using it for productivity in portrait mode, and also landscape for movies and gaming.

I cannot really see much difference between the 2. Seems like what the U2415 has going for it is the higher resolution (1920 X 1200) as compared to the U2417H (1920 X 1080).

Anyone can educate me on what's the difference? The U2415 is only around $30 more expensive so that's not a problem but what I heard is that the pixels make a difference when it comes to productivity tasks, and that it works better for web browsing as well. Apparently, on the U2417H I might have to do horizontal scrolling, which is going to be a pain and I don't want to deal with it.

I watched some videos and it seems like the screen size of the U2415 is bigger than that of U2417H? I don't know if that is true.

Also, how does the screen look? I think U2417H has a matte screen, which I don't mind since I'm going to be looking at it for long hours. How about the U2415?

Sorry for so many questions, really hope someone can help.

If it matters, i'm probably not going to use this as my main monitor long term, but more of a monitor at the side to do coding (which means it's gonna be in portrait more of the time).

Any advice? Thanks!