As suggested by @paulraphael I got myself some dextrose from Modernist Pantry. I finished the last of my first dextrose batch a couple days ago.
The mix:
Cream 600g
Milk 150g
Sucrose 80g
Dextrose 20g
Egg yolks 4 (60g)
Salt pinch
Polysorbate 80 0.13g ('cause that's what came out of the Polysorbate 80 bottle)
Final mix weight after cooking 736g. Homogenized, chilled, and spun as usual. Blast chilled to -30C. (How I love to say that.) Possibly my best ice cream effort yet. Hard, though scoopable at -18C. Possibly better to scoop a few degrees warmer.
Not sure what I would try differently next time. Maybe lower the butterfat percentage as an experiment. But I say if you have the butterfat, go for it.