Align seam on specific object

[txesc 1]

I've been chasing down seam problems on the latest versions of cura.  I print mainly curved objects without any corners to hide the layer start/stop.  I was wondering if it was possible to configure cura to place the layer seam on a specific object?  I've tried the seam alignment and layer start/stop but I can't quite get it right.  

Context - I'm trying to print multiple curved objects at once, so a small waste object is worth it if it will help the surface quality and improve the print time.  Retractions are dialed in and not leaving any surface aberrations but I have a recurring problem, not with a bump but a dent where the layer starts and stops.  It can be improved by slowing down the print but it's always present. Generally quality is nice, no under-extrusion etc. 

Thanks!