The 37.5mm PO has been discontinued for some time now; you can still find them at ADs, but when they are gone, they’re gone.

Personally hope it comes back with a refresh, just not at the excessive ~15mm thickness.

What mailing list should I subscribe to so I know what brands to like?

Well those are some beautiful photos! Really dig the hands on this piece and there’s just something about that 12 o’clock indice. 

I would NOT recommend sending it to the US Seiko service center, mine returned in worse condition. Find a local watch maker if you can.