Didn't have Don Q Gran Anejo, so made this with another light, Spanish style, column distilled aged rum (Ron Matusalem 18 year solera), along with Ango orange bitters and Lustau Don Nuno oloroso. Quite nice, I enjoyed it. For an old fashioned style drink, this goes down exceedingly easy, with the vanilla and caramel notes of the rum nicely complimented by the nutty, dried fruit notes of the sherry, with a touch of citrus from the orange. Given the base, it is somewhat light, so I'd suggest going easy on the stir count. I didn't get much from the cinnamon syrup myself (and I used a pretty strong sous vide cinnamon syrup), might try swapping out the mole bitters for the cinnamon bomb Fee Brother's Barrel Aged bitters next time.
Thanks for trying it. I haven't had that Matusalem. I don't think of the DQGA as especially light in body for its style. (Although, like all Don Q rums, the flavors are fairly ethereal—the other ingredients are just working to amplify them here.) That said, this is certainly a lighter drink for its category, compared to an OF-style drink made with a fuller-bodied or more robustly flavored rum. I used Grant's "La Garrocha" Oloroso, which is fairly intense and concentrated (as well as tannic), as a way of anchoring the structure a bit. Thanks again.