What do you mean by depends on the iron? [He's legitimately concerned about any ill-effects iron might have. Who knows in a world like this. Magic was new to him too, arriving here.

Hiccup flicks his fingers, and the measurement tape slithers to life on its own, worming its way smoothly around each body part in turn while Hiccup writes the measurements down. It's way less personal and embarrassing this way!] I'm not sure what types of metal exist here, but I imagine I could find something suitable. Or enchant something, maybe! Conjuring? Maybe...