I think I've ridden more tours in similar weather to that, than I have in good weather. That comes with the two big tours around here being the second weekend in May and the last weekend in September.

You'll be fine. Sounds like you have the clothes pretty much dialed. Put plastic bags in your shoes if you don't have shoe covers. Don't even bother attempting to stay dry - anything you do to keep rain out, will keep sweat in. Just dress to stay warm.

Be extra careful on descents and railroad crossings. Take a selfie of your rain-slicked hair and mud-spattered face, and have fun.