What about a Weiss?
Watches
A community for watch & horology discussion.
Having done this for a while and having made my fair share of mistakes, my advice is to not buy a substitute for the thing you want. Every time I've done that, I've ended up paying more in the end when I sold the substitute to buy the original.
Starting with a strict price range is the wrong way to approach a luxury purchase. You're already coveting particular items, don't confuse them with the generic idea of "buying a watch". Figure out which one of those two that you like the most and then figure out how (and when) to make it happen in a responsible way.
hamilton khaki?
The formex essence series is similar to the aqua-terra.
Reading your requirements, the 556 was the watch that instantly came to mind.
The only point where I feel it leaving is the lume, which I find acceptable, but a notable step down from the sort of lume you will get on something like a Seiko diver.
It can come across as a bit bland in images, but I would say the rs version with the coloured second hand definitely improve that, and also now the fact that this is one watch I would definitely say comes across better in real life than in images - photos don't tend to do a great job of showing the subtleties of the style, or the deep gloss of the dial that you get in real life.
Add Ann alternative, I would also check out Damasko - watches that are very much in a similar vein, but a slightly different take that you may prefer.
The obvious answer is Hamilton Khaki Field "Murph" 38 mm, or Sinn 556 as you're already looking at.
With regards to Sinn, I think 556A (with or without red second hand) has more personality than the 556I, the numbers make a nice break from the otherwise extremely sterile dial, and it also makes a stronger tool watch look. You should note that 556I has a glossy black dial and 556A has a matte dial, so they're not identical. The downside is that 556A doesn't dress up equally well, but to be completely honest no one but you will ever care about that these days — people will see a black dial on a leather strap and think it looks fancy enough. Hamilton Murph dresses up a lot better of course.