When I have worn the hood that goes with my rain jacket, which isn't very often, I put it under my helmet. It's fairly tight-fitting and doesn't get in the way.

Most of the time I wear a helmet cover in the rain, and a buff if needed for warmth.

I've got no experience with ponchos, but it seems they'd flap too much for my taste.

(Pardes, I've been wanting to tell you how much I enjoy your posts. Your writing is very fun to read.)