So I have this pretty simple sketch with a spline I need mirrored, but ANY way I try to sketch it, it fails (I've tried referencing dimensions differently, using construction lines... etc).

The thing that seems to be tripping up Solidworks is the curvature continuity of the splines I'm attempting to mirror... because if they're just tangential everything is hunky dory and SW calms its over-reactive ass down.

Every "solution" SW comes up with in the "SketchXpert" troubleshooting window simply deletes one or ALL of the relations my sketch has. And I need all of them (I think). I feel like I could just be missing some obvious conflict but then how come SW can't figure it out?

I've attached the file in question with one of the four splines I've been trying to sketch (the first one is never problematic), could someone give it a once over and with any luck find a solution?

Thanks for any help, I've been tearing my hair out about this for the past few days