This is the right answer as far as I'm concerned, though I would keep the 5 because I'd rather have the guarantee of a dodge than the extra hit point.
First thing you should consider when you get a new Setsuki hand: can I dump off a throw? If yes, then you should probably throw. Interestingly, Onimaru is another of the few characters where a T1 dodge is often not bad/pretty good because Oni's mixup is A or big normal/block. Oni really doesn't want to throw T1, so a dodge is basically 100% safe.
When something is 100% safe, you should strongly consider doing it. I lean toward throw in this case, though, because I get 11 damage off a dodge (and I can still dump), and I get 23 damage off a throw. If I'm playing an opponent who has shown a tendency to be very "get off me" in the early game, I probably dodge. Otherwise, accept the possibility that you will be duffed or A'd and go for the damage maximizing option.
Dodge and throw are actually probably pretty close in terms of value because you're going to take 20 damage a fair amount of time when you throw, but you're Setsuki. Quit pussyfooting around and get your damage in.