Help! How to change location of the start of top layers to not on a outer wall?

[Drass 0]

Help! How to change location of the start of top layers to not on a outer wall?

Why elaborate with such a descriptive title?
I am working on a thing that has a bulled C shape and I have set the layers to start inside the inner curve of the C but near the top it starts an overhang and then goes up the inside of the curve up to the top of the print. I'd like the line to not start on the edge of the print in those top layers, there it has infill but when I set it to print infill first it does't effect it because of of the width of the part. The support is one line around and the part is printed with no infill besides top layers. There is a 1mm gap between the that is bridged. When it starts the layer that is the overhang it goes to the new spot in the that is the inner most part of the C on the support but I'd like it to start above the main wall so it hides the under extrusion caused when it goes up a layer and can be smoothed by ironing. Thanks for any feedback!
1mm nozzle

1.2 line width

245c

PETG

Z Seam X 3

Z Seam Y -2.5

X,Y,Z, of 33mm 21mm 16mm

My current thought is tweek the Z seam until it sets itself inside the print but I feel like I can only get it to set on the edge. I'd like to just be able to specify with a box like a support blocker.

First image is where it starts on the first top layer, second image is where I'd like it start and third image is where it start on other layers of the print. 

[Drass 0]

I found a workaround. I added a cylinder into the C and printed it as support with support first and it started the layers in the cylinder after the normal support stopped.