Equal Gap Width

[MahaB82A]

There are two images. One is round corner with hollow closed image & other one is round corner, filled rectangular image inside the hollow image. I used transform effect to equate the vertical & horizontal gap between them but it is not precise. Is there any other way to do so? file is also uploaded.

Equate Gap

[Monika Gause · Accepted solution]

Would be better to create a new fill in the Appearance panel and apply Offset path instead of transform.

[MahaB82A]

Thanks for the help.

[MahaB82A]

I did without using Appearance panel. Please show me how to do with Appearance panel. My work video is uploaded.

[Monika Gause · Accepted solution]

THere is a method with using shapes and then applying pathfinder effects, but using strokes is easier: https://youtu.be/kbp1KoWmXnA 

[MahaB82A]

Thanks for the help.