Setting equal exterior distance between different size objects.

[sullivan_ranch04]

I want to start by saying I am not very familiar with Fusion 360 or 3D modeling as a whole. I primarily use this program to make my own Gridfinity storage units witch I then 3D print. Saying that a common time waster I fell like is setting the distance between holes where I want a socket to go. In the first screenshot you can see I simply set number to be the spacing between centers. But where I lose a lot of time is when I start having to calculate and set distance between two different size objects. Like the second screen shot shows. My solution right now is the copy/paste this function and enter the number manually. ((O1/2)+(O2/2))+3 This function gives me a 3mm spacing between the objects exterior. Is there a better way to do this?

[jhackney1972]

Please do not double post on the Fusion Forums.  Chose the one most fitting and only post once.  Your other post is here.