Lot of depends to your answer. If its summer time and its warm, no need for a rain jacket. Just ride in the rain. The cool rain will be pleasant. And if its slightly cool, say down to 50-60 F, then put on your long sleeve winter jersey and you will be fine. And maybe tights or leg warmers. No need for a rain jacket of any kind. Warmth, not staying dry, is the crucial thing.
If you are in the mountains, then staying warm is the most important thing. Wet or dry does not matter, as long as you are warm. And if you are riding your bike you should be doing enough activity to stay warm. You would need a long sleeve winter jersey, and tights, and a windproof nylon shell to keep the wind off. The wind chill on the down side of the mountain is the problem, not the rain. And the nylon windproof shell would keep the rain off too as an added bonus.
And of course, remember when you are touring you can change your route or daily mileage. If its raining, just ride a couple hours and stop for the day. I did that in Portugal in November 2000. It was rainy so I rode about 30 miles and stopped and wandered about the town. Then continued my journey the next day no worse for riding in the rain.
My rain kit consists of a waterproof nylon jacket and pants. I wore the pants once 13 years ago. I've worn the jacket a few times more than that. I'd advise concentrating on staying warm with a long sleeve jersey, tights, arm/leg warmers, and keeping the wind off to aid warmth with a nylon type jacket. And a balaclava and gloves for warmth. Water doesn't hurt you.