As everyone's metabolism is different and their insulin/carb ratios are different it is impossible to say 'you should use this or that ratio'. It's great that you are wanting to sort it out and there is help out there. Have you looked at whether you can get on a DAFNE course? That stands for Dose Adjustment for Normal Eating and teaches you all about your diabetes from the how and why it all is as it is, to how to control it by understanding how to work out ratios, when and how to adjust them etc. I went on one after over thirty years with diabetes and I learnt more in that five days than I had ever learnt in the whole last thirty years. I now do not fear going hypo unexpectedly all the time as I used to: I'm no longer afraid of being and working on my own because of DAFNE.
Ask your GP, or better still, your diabetes nurse as she (he?) will almost certainly know more about it, if they can get you on a course. If there is not one soon that you can go on, and they get very booked up so it's unlikely to be soon, then ask if your nurse can teach you. I don't even know if all diabetes nurses are DAFNE educated themselves, but if yours isn't, ask them to find someone who is. There are lots of people on here who might be able to advise too. I think there is a website with DAFNE type instructions on it, but I don't know where it is: someone else will know I'm sure.
Good luck with it all.
Margi.