That's what the pattern sounds like, left and right front at 34sts each for the cardi. The 34 sts gives quite a bit of overlap for the fronts but that's what the pattern is calling for.
Yes cast them onto one circular using 2 separate bals of yarn. If you work them both at the same time you'll be sure that they're even and the shaping and sleeves are on similar rows.
Good luck with it and post a photo if you'd like. We'd love to see it.