Mike, I have used Tresiba once daily in the AM for over a year at roughly 0.25U/kg pf body weight. Recently, for unknown reasons, I experienced nighttime BG higher than I wanted. I switched over to half of my daily basal twice daily (8AM and 8PM) and it has knocked those nighttime BGs back down to satisfactory levels.
I am not sure if this nighttime BG issue was caused by the Tresiba duration (I have heard 42 hours), the timing of the Tresiba peak (which I interpret to be at 4 +/- hours for me), or possibly I was developing some insulin resistance due to less activity? Before trying the AM/PM basal, I gradually increased my Tresiba AM dose by 20% with no improvement at night but more lows in the day so I gave that up. At any rate, twice daily basal works well for me.
I like the fact that Tresiba’s basal action is pretty mellow…I switched over “cold turkey” one evening without ill effects. Sunday AM, Monday AM I took 20U, Monday PM, Tuesday AM, Tuesday PM and onward I took 10U.