Love everything about your post.
Interesting about your experiment keeping the red maples separate.
I did this with my norway maples (versus sugar maples) in the 2021 season, and the norway maple syrup was consistently lighter, and perhaps more of what you're describing as buttery.
At first I concluded the norway maple syrup was quite different from the sugar maple syrup.
But now I suspect it is because I had far less norway sap versus sugar maple sap, so the difference was more related to batch size (just a theory).
One batch of norway maple syrup was made from just ~3 gallons of raw sap, to give you an idea of how small a batch I'm talking about.
If you get in the mood for more experimentation, it might be interesting to see if you can get the same results from a very small batch of sugar maple sap.
2024: 28 taps, 7 gallons. RB5 purchased but not opened :-(
2023: 30 taps, 17 trees, 11 properties, Sugar Maple & Norway. 2x3 flat over propane & kitchen finish. ~11(!) gallons.
2022: 9 taps, 5 trees, 4 properties. 3 hotel pans on 3 Coleman 2-burner stoves burning gasoline; kitchen finish. ~3 gallons.
2021: 2 taps, 1 sugar maple. Propane grill then kitchen finish. ~Pint.
All years: mainly 5/16" drops into free supermarket frosting buckets. Some plastic sap buckets hanging on 5/16 sap-meister.