Dumping, just like pretty much everything else to do with these surgeries, is very individual and varies from person to person.
I've never dumped very often or in a horrible, sick to your stomach manner. Early on (under 3 months) I was quite sensitive to sugar and fat and once or twice did feel queasy and had to lie down after a yoghurt or something slightly sweet. But now, nearly 9 months out, I don't get that anymore and I can eat pretty much whatever I like. I do feel tired if I eat something sugary or a bit more fatty, and I'm told by my team that is a mild form of dumping (I just start yawning incessantly right after eating, and feel a bit bloated, just very very tired, for about 30 mins).
I think it's great if people try to stay under 5% fat/sugar for the rest of their lives. Personally, it was always my long term goal to eat a NORMAL diet. Like every other normal sized person out there. No excesses, just balanced nutrition, a little bit of everything, in slightly smaller than average portion sizes. And I am extremely glad I can do that now and still continue to lose weight as well for the time being.
You will soon find out after surgery how your body reacts to certain foods. And it is also worth knowing that even if you dump on a particular food say in month 3, that doesn't mean that a few months later you won't be absolutely fine eating it. I was much more sensitive early on.
Think of your new stomach like the one of a baby - you wouldn't give it fish and chips when it's a newborn - so bland and boring at first and then you work your way to a more normal diet over time.