Working on a model that involves numerous equations and global variables.  Circular structure divided into equal segments.  Currently I have a single segment as an assembly and do a circular pattern to give me the full structure.  This assembly needs to be easily modified for different diameters, number of sections, etc.

My question is: I have varying number of legs dependent on how many sections and i need to place several sets of X Bracing between these legs.  The leg is a sub-assembly with tabs spaced at various intervals for the X to bolt to. (Model I am working on now needs 4 Xs in the height of leg and there are 18 legs around the structure) The X Brace is a channel with holes at either end.  I need the X to remain at 45 degrees.  

How can i go about setting it up that as I modify the assembly, two things happen: the X brace changes length to remain constrained to holes in mount tabs, and tabs move vertically on leg to appropriate position? This X Brace will then be propagated around the structure using the pattern driven pattern. 

In a similar structure I modeled, I left the leg sub-assembly flexible and constrained the tabs to the X  Brace in main assembly allowing it to align perfectly.  However, I made a shop drawing from the sub-assembly and learned the hard way that in the sub-assembly, the tabs were NOT CONSTRAINED, and it was only discovered after they had been welded on.  Thankfully there were not a lot of them as they all had to be cut off and moved!