Sorry this is so nerdy and hard to follow but here it goes. I have been trying to learn about the 1983-1985 Ritchey and Fisher period bikes.
Note on the geometry. I have measured with a smart phone app setting the 0 with floor and keeping the bike as straight as possible on its rims. But I'm sure I'm off by more than 1 degree. I imagine very carefully aligning the right size protractor could be used as well, but you are right on the way to go.
About your bike. I do think that long chainstay belongs to an older bike. The 1984 Palo Alto gives the chainstay length at 17 3/4" for a 22" like yours (see insert), and it used threaded BB, and the water bottle braze-ons were on the down tube just as the 1984 Mt Tam (special orders were an option on Everest, but I imagine special orders were a decision of the client and his money).
You may have a rare late MT Tam. I know MountainBikes MT Tams were B frames in 83, they may have changed to T in 84 and they did for sure in 85, but I imagine Palo Alto MBs were B frames based on 83/84 MT Tams. The 1984 MountainBikes MT Tam had a 18" chainstay and had the pressed-in BB. We know Ritchey sold Mt Tams to MountainBikes until late 83, so its possible some early 84 MountainBikes MT Tams (Fall/Winter 83 made) bikes were made by him as Teesdale took on the MountainBikes contract in January 1984 and may have taken a time to start spitting out frames.
I'm unsure who owned the MT Tam's name but the early 1985 Ritchey catalog (the one with many typos) mentions that the Timber Wolf replaces the MT Tam. For what one can read there the Timber Wolf was a new model for 85 and it likely came with a threaded BB ("Ritchey special sealed" as mentioned in the 84 Palo Alto, when it was threaded). Reading between lines that catalog says the Commando was introduced late summer 84. The Commando was basically a cammo-painted version of the MT Tam. So it appears that either Ritchey was still making MT Tams for MountainBikes until Summer of 84 or that he was selling bikes under the MT Tam name or that he considered to be MT Tam for the first half of 1984 simultaneously with MountainBikes.
So if your bike is an 84 as suggested by the long chainstay it may either be an early Ritchey-made 84 MountainBikes MT Tam or a Ritchey MT Tam from that 84 period post relation-end with MountainBikes with a special order on the water bottle bosses location. Or your tape measure is stretched out
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Nerdy and confusing enough?
Nevertheless a good rescue