For Roubaix yes. I don't think he's too light for De Ronde per se. I think the question would be how much the cobbles in Vlaanderen would wear him down or if he just has to close too many gaps because he can't follow on those hills?
I think he's more likely to win Vlaanderen than Sanremo, although it's pretty likely he'll never contest Vlaanderen in his career.
Yeah, I meant Roubaix, but was in a bit of a hurry.
Ronde is a question mark in terms of battle for position and obviously 1 minute power output against 10+ kg heavier guys. And obviously good luck sneaking away from Van der Poel/van Aert on flat road.