I would stick with 130/180 for your rain tires. Then you will have a uniform set that you could use in low grip dry situations (if you needed to) and one less variable to worry about. The great thing about rain racing is that it is a lot less dependent on minor set up details (like wheel widths).
130/180. You might want to consider Spoked aluminum wheels. Spoked wheels should provide more grip which can be helpful in the rain or low grip conditions.
Here is something on wheel design that you might find useful.