Regarding your question about the toothpick test versus having the top spring back, I’m not sure. A few cakes (like the plum-bluberry upsidedown cake from RHC) have crispy crusts that can wipe a toothpick clean as you pull it out, and the harder crust can also seem resistant to a gentle poke, even well before the cake is finished. I haven’t made your recipe, so I don’t have any experience with the sort of test that works best.
My fail-safe method is to take an internal temperature with an instand-read thermometer. I do this in conjunction with other methods, taking the temp when it comes out of the oven, but it’s a great confirmation to have, because if anything goes wrong (or I want to duplicate a good result), I know exactly whether or not it was over/underbaked. The only drawback I have found, is that it is not only reaching the right temperature that’s important, but reaching it in the right amount of time- i.e., if a cake takes longer to come up to the right temp, its texture can suffer and be dry even though the temp was correct.
Most butter cakes do well from 190F-200F, while many breads go to 205F.
With larger pans, cake strips to protect the sides and an inverted flower nail or heat core can help promote even baking.