I think I understand a bit the OP’s concern, but there’s not a very clear answer. It depends a lot of what tools finally are mounted and how.
My first build, which I kept pretty short, but not as short as yours, I have to modify as the T8 goes through the floor.
My other build which is running more or less, lost quite a bit of mm just the way the router was fixed. I guess this will be further reduced when I change to ER11 collet.
I’m thinking already, depending on the job, to have parts ready to interchange.
Longer tubes for the legs would be the easiest, I’m thinking already about a complete Z-axis replacement in different lengths.