Why? Because you already have 2 Radiomirs - PAM246 & PAM249 - and only 1 Luminor. So mix your collection up more and get a Luminor 1950 case which is different than the standard Luminor case that the PAM0 uses.
- AT
How do you find the size of 249? Would you prefer yet another time-only watch or you a bit of interaction w/ a chronograph watch? What draws you to your next Panerai, the simplicity of the dial or the unique in-house monopusher chronograph that powers the 317? Do you think you'll stop at 4th one or you think you'll continue to go on? How'bout the evil thought of owning both?
Given what you own, I do agree 317 seems to complement your current collection better but none of these opinion matters more than what you heart is telling you...
Good luck & keep us posted!

but why not a 9 or 4..a. I am try to stir your mind,LOL.. Stick to 339.
Regards
John
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I would add another...
my choice...