I'd love some input on how to fix bad looking taping seams. These seams are both on butts and tapered edges. Especially in the ceiling planes you see the seam kind of bulged all the way down with a center line which you can sometimes feel, sometimes not. On walls you can feel the bulged area with almost a discernable ridge at the line. I think this line probably has to do with the mud sagging the tape out but not blistering it-the tape is not bubbled or cracked. The walls are spray painted. I've tried feathering these out, but have had only limited results. It tends to telegraph on the bulged area so in trying to keep it as flat as possible the shadow line still shows. Any suggestions would be appreciated.