Perspective/non-linear blends with a common centre

In illustrator, if you want to take a blend between two objects with a specified number of steps and give it a perspective-like effect – changing the curve of the blend from linear to non-linear so the blend has different density at different points – it’s pretty straightforward. You add a spine to the blend and edit the spine until you are happy with it.

Step and repeat for offset path – Illustrator

In Adobe Illustrator, is there a workaround to easily repeat the process of offsetting a path? Just as you can input the number of desired steps using the blend tool, is there a similar option for the offset path command? I am also wondering why it isn’t possible to constrain proportions when using the blend tool with irregular shapes…