On metformin measure in the morning  right after waking up  .
Initially I did measure also right before a meal  and also 1 hour after or 2 hours later depending on How fast spiking carbs I ate  . Now I mostly measure blood glucose when I have been eating What I find is too many carbs in 1 meal . In my case more than 40grams of carbs  or more . Because of my weightloss and very much exercise it seems I many times can eat that amount almost without a spike and usually be lower  in one hour  than 6.5 mmol. And in bad situations under 7.5 mmol . Lately I have two days experienced a much raised morning blood glucose for no actual reason . Still dont know why But Think now I must have had a virus  or have been ill without noticing  . Actually I do Think I am in remision.  But will keep taking care and getting fitter  it really pays healthwise if one can do that ... This night after eating both 2 Big potatoes and two candy "cream- tops"  with sugar like around 30grams  so all in all like 150 grams carbs and my number was only 6 mmol  both 1 hour and 2 hours after 

 well except from that I am still on metformin