Why do you think you were slower up that initial hill on the Bkool trainer by the way
I cant think any particular reason other than I wasn't sure what wattage would be comfortable so waited for my HR to catch up and settle into my effort, so probably eased off. I was trying, as seen by my HR, but its really quite different from Zwift. I can spin up 53*11 in bkool, actually I was thinking I need a 54/55 ring for a descent, because all it does is push my HR to near max pedalling over 100rpm for long stints