I prefer to use Xert workouts in the “real world”. My most convenient loop is about a 53-55 minute loop. I would like to be able to take the standard workouts and “trim” them to fit this window. In some cases, I can just chop off the cool down component but that doesn’t work for those that start at about 1:10 or so in total duration. So, a quick way to “fit within a time window” would be great. I would then chop off the cool down and apply the “shrinkage”. I realize that if this was done to compress a 2 hour workout to 1 hour then the purpose of the original workout might very well be lost but I have to imagine that a 10-12% reduction would not dramatically affect the value of the workout as designed. This “trim” function could also work in the other direction if the standard loop was, say, typically an hour and 15 minutes in length.
A simple alternative solution would be to make the intervals based on a Target MPA and you can then shorten / lengthen them as you’re riding to fit your schedule by simply adding/reducing the intensity. (Inverse is true for recovery intervals).