No not at all. If you know your 5 min and 20 min, they will tell you and us where you will be
I will get the dumb turbo set up in the next few days and see what numbers I come up with.
For 5 minutes I would aim high and just try to hang on.
Pacing for 20 minutes isn't so obvious though. I am pretty sure that I can do 210 W, think I might be able to do 220 W, and there is a chance that it might be a bit higher.
Would it be better to start safe and do (say) 210 W for 10 minutes, 220 for the next 5 minutes, and whatever looked possible for the final 5 minutes...?
OR start high and try to do (say) 240 W for 5 minutes, adjusting target again at 10 minutes, and 15 minutes?
OR Start in between at (say) 225 W and see how that went, adjusting up later if possible, or down if necessary?
You can probably tell that I have never done this kind of thing before!
*****
I just watched a ride on the Mayan San Remo route... I liked the look of that.