RDAOU and others.
Looks like I spoke too soon. Not where I need to be with this. First off I have 3 different size columns and unless I can dimension from face to face some how and have and just apply the equality constraint to those dims only then I see no way of making them all the same. In my way of looking at things dimensioning center to center probably has no meaning in this context.... but I could be missing something.
Seems to me that I should be able to somehow dimension the overall dimenison (per RDAOU's example).... (because the columns are objects and are of fixed dimensions anyway) then "simply" dimension face to face of all the differing columns and make that work somehow.... but no way to tie those dims together and apply the equal constraint. So would need to somehow do a string of dims and RDAOU's example does that but that is not the dimension that has the equal constraint applied. When I create this way it does not work.
This is what I get RDAOU's way. Top 2 "overall" dims are locked with the active dimension string having the equality constraint activated. Note that the 2 outside column dimensions are different than the interior column dimensions

This is what happens if I change the lower dimension string to face of column at the exterior columns. Similar to above but wider spacing at outside columns.

This worked as I would have expected it to BUT BUT BUT I had to remove constraints in the model to get it to work AND AND AND it CHANGED the OVERALL dimensions which is an obvious complete deal breaker.
Can I not have my walls below locked AND the columns at the end (corners of the building) be located and locked at the 1-1/2" location dimensions as is the case in all the examples?
Short of removing/ unlocking the 1-1/2" dims what other possible constraints would I need to think through to make this work?
If I could even get 2 different size columns to work then I could go back in and center the 3rd intermediate size column between them individually and that would be progress but I can't even make that work.
Seems to me the only way to get this to work would be to assign a point on the face of the columns as the points to dimension to in a manner similar to the way I would handle this situation in vanilla cad.
Assuming I can't make this work with the equality constraints, wondering how everyone would handle "best practice" so at least some of the repeat work would be eliminated if changes occur down the road.