Agree. There was actually some thought for this rack. My "old" lathe had something similar to George's but was made from an extra 30" DRO scale cover. After I saw Tom Lipton's, I realized what I wanted to change.
The dimensions of a BXA holder are height (to top of adjusting stud) 3.3" and width 1.24"
Using the length of my old holder at 30", capacities are as follows:
A horizontally oriented holder, like my previous one or George's - 9 toolholders
A vertically oriented holder, as my new one is, with 1.8" spacing - 16 toolholders
I could have reduced the spacing to 1.5 inches, then - 20 toolholders
So, with my current 48" SuperStrut holder, 1.8" spacing allows 26 toolholders and 1.5" spacing - 32 toolholders.