I need to create a slot along this spline (on surface). The spline is in a 3D sketch. I need the slot to be .193" wide all the way through. I've tried to create a sketch and wrap it around the tubing but I can't locate exactly where I need the hole to be on a 2d sketch. I've created both endpoints for the slot and I just need to know how to create a clean cut that is the follows the same thickness as the diameter of the circles (endpoints). Using swept cut has not been working out for me, as It seems to not want to follow the path I've laid out. Any help is very much appreciated, thank you!

I've attached photos and the part file.