What was the original question? Is this so you can guess at how to pace an all our 20min or ftp effort of 45 to 70min? Or is this to do mental math on a guess of all that from what you did already.
Posting the actual numbers was irrelevant, as the method is what matters.
Either way........just go with 20min and 92%. I've not met someone that can do 95%. They exist, but 95% is a very optimistic figure for most folks.
Thing is, with bikes if the effort isn't controlled enough the math can get dodgy. With running, there is SOOOO much data on pace, HR, age, and VO2max with running also not having a sufficiently troublesome aerodynamic component that stuff is charted well enough your Garmin is pretty good. So, most folks with bikes do it indoors or if blessed with a really flat boring 4-corner 25mi TT or a long steady climb that isn't too steep.