assetHistory has a mode for hourly data, but the manual only lists Bittrex and CryptoCompare for this mode. I tried using it with IB and while it looks like it kind of works, it produces a kind of corrupt history that looks like the image below. I'm assuming this means that this feature does not properly support IB? It would be a nice option considering minute data takes a day to download for a single asset due to their API limits.