I got a pair of plain leather reins in 1/2 inch for the curb. I found better quality for the price going that way instead of specifically getting curb reins. So they have a buckle instead of the little slider thing, no big deal. If you google plain reins 1/2 inch, you'll get more options. I think I got mine through VTO on one of their sales. Then I use a pair of regular snaffle reins for the snaffle. Use what you are comfortable with for the snaffle - why change what you are already familiar with?
On the subject of reins - Has anyone seen BROWN curb reins WITHOUT the middle buckle, and with hook stud ends???? I've got black ones that I just love, but all of my tack is brown, and I have had no luck finding any!
I didn't find the right solution from the Internet.