A stainless steel PML could be what you're looking for. You can sample the design on your wrist, and see if anything about the GO feels "lacking", compelling you to seek a Lange 1.
I own 1 of each brand, although very different styles. A steel SeaQ 39, and a Lange Saxonia. Personally, I prefer the darker color hue of German silver used in the large Lange 3/4 plate. That large Lange plate glows, when you rotate the watch back & forth under different lighting conditions. Check out the 2nd photo in this article: https://blog.crownandcaliber.com/splurge-vs-steal-lange-1-vs-glashutte-original-panomatic/
But with the GO PML, you get double swan necks and double the engraving! Plus convenience of automatic winding.
What generation is your SMP? If it's one of the 1120 or 2500 caliber ones, I think you're spoiled with a comfortable thin watch
The thickness of the PML might shock you. With its almost-brutalist tall long slab of just vertical steel on the side profile, in between the bevels on the top bezel and caseback. In comparison, the rotating bezel makes up a sizeable portion of your SMP's side profile, breaking up the monotony of a tall vertical case height. Definitely worth checking out both in person, to see if the case height on either a Lange 1 or PML interferes with your enjoyment of this watch design.
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