200m Pacing: Even? Positive Split?

I have read various swimming books that tout even-pacing for 200m as the best way to go. So, using my very modest goals as an example, if I want to swim 3:04, I should aim to do 46sec every 50m. (Diving in would likely make the first 50m faster, but let's assume that I am pushing off for this discussion.) But I'm beginning to wonder if something like 44.5 - 45.5 - 46.5 - 47.5 = 3:04 is the better way for me to get to 3:04. In running, the 800m is typically performed in a positive-split fashion, due to energy requirements for the event. A 2:00 runner (hey, that was me!!) would likely do 58.5 - 61.5 halves. Rather than kicking the last 200m, you would basically try to hang on, or minimize the fade. I sense that the 200m swim should have the same characteristics. At the WR level, the duration is close to 800m running. (I suppose that if I was able to examine the 50m splits on various elite 200m swims, I would have the answer to this, but I haven't been able to dig this information up yet.) Anyway....I've been stuck at 3:05 for 3 weeks in a row, utilizing quite even splits. On my 3:04 (or 3:03?) attempt tomorrow, I'm aiming to do the positive split. It's not "sexy" to be "just trying to hang on" on the last 50m, but I am wondering if this is the way to a faster 200m. Thoughts? Thanks in advance.