Sorry I know this section of the forum is for Garmin Connect, but I couldn't find one for the Garmin Fit app.
I love using my iPhone as a bike computer because of the large screen, all the easily available info and the maps, but it's really annoying how the screen layout is locked.
I personally want to know my cadence, hr, speed, distance and time, but to see all of these I have to flick backwards and forwards through the screens, which can be very awkward to do with cycling gloves on. It would be way beter if you could personalise your screens to show the info you want. The mapmyrun app is far superior in this department, it's just a shame that it only works with the Wahoo dongle which costs twice as much as the Garmin one.