Morning good luck Gill with your efforts and as others have said it is a very individual thing and is as much art as science.
So yes you can use general principles insulin but constantly need to fine tune to best manage your timing of insulin and of course the situation is in a constant state of flux.
I know I have only being diagnosed 9 months so still very early in my journey and yet to get challenged by it over a long period of time.
However I try and stay in control even if I get it wrong rather than it controlling me and what I mean by that is I set the agenda as best I can.
So I have a general pre meal bolus and ideally 10-15 minutes but it can vary depending on prep time,BGlevels etc so I can end up taking it just before meal or even after meal or split and it seems to work fine for me.
I do get these decisions wrong so try and take corrective action like a walk but that is not always possible and I tend to react to situations.
However it causes me no stress whatsoever and I find it does not cause me any issues and in fact my stress levels are very low and I see my diabetes more of an inconvenience rather than anything more challenging.
I do appreciate that I readily accept health challenges as just being part of my life am lucky in that I can cope with events as they occur but just reinforces in my own mind that it is a very individual condition which governs our responses and the only constant is it’s challenges and the support you get on this forum.