@bujanin, about sorting out one's basal: our bodies basal requirement is different at different times of the day and basal testing is generally done so that people can find the best dose of basal for different times of day. This is appropriate and necessary, particularly when dealing with split basals, eg levermir, where each split dose only lasts part of the 24 hrs. But Tresiba is different and needs a different mindset.
Because it is simply not possible to have a daily Tresiba dose that provides varying basal cover across 24 hrs one has to optimise the steady Tresiba release for best effect over a part day and most people make that for the late evening into and through the night. One major part of basal testing is to assess how the basal is doing in the absence of bolus or food and for many of us that coincides with that period from late evening and through the night. So it is possible and indeed relatively easy to assess how one's Tresiba is doing from 10 or 11pm through to 6 or 7 am (or longer 'fasting' hrs) simply by definitely making that a bolus and food free period for that one period of basal test - in conjunction with the CGM graph for that period. I would suggest also with a confirmatory finger prick at start and finish; this fp is just to confirm that CGM and actual are broadly in unison over that period and thus the test period is broadly valid. It really doesn't matter if there is a bit of variation between CGM and actual. But one is looking for a horizontal graph, ie level trend over the test period.
So far so good: if the test period shows a horizontal trend then, even if higher or lower than wanted, the actual Tresiba is fine during that period and adjustment might be needed to get a better start point, then arrive at a better finish point. If trend is down, then the basal is dominating that test period and needs reducing. If the trend is going up then Tresiba needs increasing. Tresiba changes should be done in modest steps, using trial and learning to arrive at the optimum (horizontal/level) graph. You won't necessarily get a perfect flat graph (on this forum people sometimes refer to an overnight 'flatfish'); perfection is not realistic. Just start and finish at about the same point and not too much waviness in between.
But here is where Tresiba is different and needs that different mindset.
Firstly, as far as I'm concerned no point in splitting Tresiba; in my opinion doing so is a waste of time and attracting the risk of forgetting one of the split doses from time to time.
Secondly, by day you have to manage your BG using bolus, exercise/activity and eating. The Tresiba basal will be doing its stuff throughout the day, but just not necessarily providing exactly what is needed to precisely cover glucose releases from one's liver, etc. In effect one either 'sugar surfs' or 'chases the insulin' - depending on what one's BG is doing on any day. In practice this is normal BG management that we all try and do, with all the everyday complications of carb counting, bolus ratio assessing and then dosing, along with the adjustments we try and gauge for different levels of activity and exercise on different days (and for weekends vs weekdays). Plus the adjustments we need to for those other things that somehow seem to come from the ether and have affected our BG!
Thirdly no change to Tresiba doses until it becomes apparent that the basal needs adjusting because of long term changes from, perhaps, weather seasonal variations or maybe a definite change in exercise regimes; long term illness, perhaps. But fundamentally when after several days it is clear that the Tresiba dose is no longer right. I seem to only need to adjust my Tresiba no more than 4 times in 12 months.
Fourthly, just because one has optimised Tresiba for the ideal night, it doesn't mean you can't ever change the 24 hr routine. I sometimes have a late evening snack and bolus for that, or change my evening exercise regime, or drink alcohol close to bedtime (alcohol and insulin aren't great companions for me, so I need to make allowance for my liver behaving differently in how it metabolises my evening meal or late snack). BUT I just need to keep in mind that I may have varied the evening and night time parameters and so may need to adjust my bolus and eating thinking for that period. I also need to gracefully and accept that my overnight CGM graph was altered by my chosen regime changes.
Fifthly: because you are not trying to optimise Tresiba for daytime, just accepting that it is doing whatever it does, then "basal testing" has become very simple. Just do the test for evening and night, with due exclusion of bolus and food in that window, with no need (or point) to test across other time periods.
Tresiba may not be ideal for everyone, it's just one of the tools available to us for keeping us alive and managing our BG. But with understanding of what Tresiba is intended to achieve it can be a really good basal and just needs awareness of how to get the best out of it. Just depend on Tresiba for its consistency for part of the 24 hrs and then use bolus, exercise and carbs for the rest (easy written - far from easy to do sometimes).
I can't remember if you have previously done a DAFNE course. But if you are intending to ask for a course in the near future, I found rhe DSN leading the course I did kept emphasising the need to adjust bolus ratios or basal doses; I had to politely remind her that did not apply to me withbTresiba as my basal and by the end of the 5 days she was including the comment "but not with Tresiba". I didn't need to be told, but good to hear it openly said. Good luck.
