Hi
I too am due to change from levemir to Tresiba.
I chose the penfill option as i use a novopen echo as that is what i use for my levemir.
I talked my GP into this by actually demonstrating the memory function in her insulting room.LOL
I take 10 units am and 14 pm currently but when i change i'm going to start on one dose of 16 and am armed with a sensor, novorapid, jelly babies and my wits.
I don't see a specialist or DSN as i've been doing my own thing for so long i am used to it and my libre and me are at one but we are all different so i never recommend my way of doing things!
I wish you well and do please keep us posted as i've still got buckets of levemir to use up before i change.
Tony