I agree about it being very personal. I tried FODMAP (and other diets) under care of a dietician at the hospital, didn't help me but difficult to stick to rigidly, lots of things cut out and can get quite expensive, a lot to invest in it but it has apparently helped a lot of people.
I have another malabsorption condition though as well as IBS and get bad indigestion and reflux.
I find Buscopan helps for the cramps and take it pre-emptively on prescription. I also have a daily bio-whatsit yoghurt.
My tolerance to things chances randomly, I've had to cut out things for long periods then found I can tolerate them again, such as dairy.
I have bowel rest type diet episodes when I try and just stick to very simply light meals with things I know I can tolerate if things get really bad.
Wholemeal/grain is something I can't tolerate very well. Soft cheese is another current one.