As you say experimenting is the key strategy in good management of blood glucose. There is no one-size-fits-all and this is slowly dawning on those that call themselves expert in the area of Diabetes.
People tend to get too hung up on the accuracy of cgm versus finger prick test but as long as the margin of error between the two is not more than 20% (that's a fifth in difference) then that's ok. In any case it's best to focus on trends as these can tell what foods affect our bgs and maybe how they affect us.
What I'd like to see is a manual or book that explains how to get the best out of cgm data. I've got a basic knowledge of stats but I'd like to learn how to interpret the stats and make use of those interpretations.