Which one should I pick?

I'd go for the gray Rado. Grey is more classy than green and will look good in many years to come. Green is a trend and it might look "old" in a few years. I might be wrong with that but I'd go for the grey Rado. 

Thanks for the input! Truly appreciate your comment 😀. I think you’re in the right about this one, green might be trend that would surely dissipate at some point in time and I should go for something more classic and stoic. That said, I guess I should’ve been a bit more specific. My current lineup of watches I own are a 36mm Rolex Explore, Omega Aquaterra in Blue, Sinn 556 I Blac, Seiko Sarb033, Nomos Orion etc. Point being I’m afraid I may have too many black/white or monochromatic dials in my collection. Which is why I also suggested the Green variant. Ever that you’ve said still stands true. This is just an additional information to see what you’ll do in my position. As always thanks a lot for your feedbac! 🙂

Would the 37mm variant be better for you?

The 42 has a lug to lug of 49mm. I also have 6 inch wrists and the max I can wear is 48mm, but usually aim for less than 46mm.

Jeez, I dunno. Cudos for picking apples and apples. Doesn't seem to happen very often. Those are two that I've considered myself in the past. I love the whole BP inspired retro diver look. The Rado seems a bit dressier to me, the Squale a bit more shorts and flip flops IMHO. Rado is going to be more, but you could get closer by going grey market. I'd need to try them on to make a proper decision for myself. I wouldn't do green personally, but that's just me.

Here's an idea - any way you could order both and return the one you liked the least?

I have a grey dial TAG and it‘s extremely versatile.  Goes with anything.

The 42mm wears quite small compared to other divers. It’s very comfortable on my 6.3/4” wrist. 

I’ve owned the Limited edition 37mm and I honestly found it to be too small even for my wrist size. The 43mm compact lug with the ceramic bezel makes it feel substantially smaller.

How do you like the Green dial? Is it very shiny in most lighting situation?

I found it very crazy under the AD’s lights but very changeable under different lighting conditions in the real world. 

At the AD:

Later:

Thank you so much! The outside shots are amazing and something that people often overlook. You’re very kind for allowing me to see the Rado in Green in its outside environment. Thanks!