I don't know for the location of your things but I know on my bike I have all I need on my road bar (iPhone as I need my music while riding) and my Polar. And both I have extension so I can look at those without lowering my head too much. So I only need to lower my eyes a bit and my numbers are there. I don't play with my iphone while cycling. If I want to change a song I wait until I'm really slowed down, or stop (while taking a sip of water). I try to look ahead and use all my peripheral vision all the time and anticipate my next move, if one needed. Only then I will look at my "toys".