.. hello Jared. Welcome to the Lange world. I am not such a long time lange lover either myself. You have very good replies so far. But with all due respect to other replies you have received so far, here is what I think, what I personally think.
I believe that being "dressy" means sometimes smaller watches, rather than larger watches which may dangle around your wrist showing out of the sleeve. Here I assume that you wear the long sleeve and potentially jacket when you say "dressy". Being dressy can be somewhat discrete, as opposed to playful, show-off, flashy. When someone meets you for the first time at an official event or occasion, you do not want his eyes glued on your wrist. The watch does not have to show out of the sleeve, may be half is okay. I have made all my business shirts so that no one sees what watch I wear. (Disclaimer: the different situation calls for different meaning of being dressy, I admit!)
Sorry for being long, but with your wrist size (mine is 6.45"), I would recommend something much smaller than 39mm. Lange 1 or L1 MP may be Okay. You are also in luck because there are still 36 or 37mm Langematik, Saxonia, 1815, 1815 U/D are still available in the pre-owned market. My recommendation is to look for those discontinued master pieces in the pre-owned market. The color would be your choice, but I would prefer white metal for "dressy" watch in my definition.
Good hunting and please let us know and share some pics when you have decided.
Ken