After a few tries, I finally settled on a keeper 39mm Railmaster. I was surprised that there is yet to be a review of it in the reviews section (I'll be doing that shortly).
I was pleased to see how well it pairs with another favorite of mine, the Seamster 2254.50 (currently on a 2 piece NATO):

As a mater of fact, the case diameters are such that the bracelet end pieces are totally compatible, in other words, the bracelets being interchangeable.
Coming from a long history of owning Rolex Oyster bracelets, I was never really in love with the small polished trims of the bracelet's center links. Here's a nice look that reminds me of the more classic Seamster models:


Of course, the Railmaster clasp (what I humbly consider it's weakest feature) is inappropriate on a diver...

...Not to mention the Seamaster's clasp is one of the best designed in the industry...and I almost did a little bracelet surgery transplant of the clasp from the Seamaster, but decided against it...(If I ever decide to do so, I will certainly update this thread)

The case of the 2254.50 SM (41mm) and the 2503 RM (39mm) are very similar in lug length and shape:

Obviously, the dial diameter of the 39mm Railmaster is wider than that of the Seamaster.

But it looks like the lug length and curvature is right on the money.

So what's the point of all this? With 4 different modern Railmaster sizes available, I had a hard time deciding which was best for my 7-1/4" wrist between the 36 and the 39 and actually purchased and resold a 36" version.
So if the 41mm Seamster fits you well as it does me, IMHO, the 39mm Railmaster would be your choice, assuming you want the same feel on the wrist.

Thanks for looking

 

Nice post. I would love to have a 36 or 39mm Railmaster someday. It would be great to see wrist shots of the two sizes as I also have about the same sized wrist.

 

Well done. The 2254.50 is a great watch.
I haven't decided yet between the Railmaster 39mm or the Explorer I 39mm. The Omega being half the price (used) I'll most likely go for the RM. Nick Hacko (watch dealer in Sydney, Australia) has done a review on his website about the two.
Good information about the bracelet fit. Makes me wonder now if the Omega curved ended rubber straps for the SM is going to fit just as nicely on the Railmaster. I may find out in future.

 

I can certainly oblige with some wrist shots, however, to make it easy, I would to point to my contributions to a wonderful post on this very subject by Workahol on WUS. I am DIV on there as well and my wrist shots start on page 7. One thing to note: I incorrectly thought my wrist was 6.5", but it is actually 7.25":
http://forums.watchuseek.com/f20/tale-two-railmasters-1056263-7.html

 

Thank you for the link. Teeritz's write up was leaning me toward 36mm but from your photos I might lean toward 39mm now. I really think they should have just released it in 38mm as in the original.

 

I agree 100%, Giff.
Omega should could have saved a ton of money and resources on making a 38mm Railmaster and been done with it....OK, if they absolutely needed a larger one, make a second one at 42mm...and then that's it..."put the instruments down and walk away, Omega...."
Take home message is that if your wrist is less than 7" go for the 36mm, around 7" either would work, 7-1/4" or more 39".
8" or more, go for the 41".

 

Nice thread Dan, thanks for sharing!

 

One of the biggest hangups I've had in pulling the trigger on the Railmaster... 36, or 39? Not exactly like I can try them both on at an AD any longer. Thanks for the comparison shots, especially the back to back. I'd been leaning towards the 39 but a lot of the reviews I've read comment on how it wears so much bigger than other watches. I think I'm more sold on the 39 now.