You can use 'Before' and 'after' to add the variables into a particular location in the table.
Note: you will need to supply values for all of the rows at the time you add the variables.
Much of the time it is easier to do something like
T.par = appropriate values
T.type = appropriate values
T.trial_no = appropriate values
T.vel = appropriate values
T = T(:,{'par', 'type', 'trial_no', 'vel', headers{:}});
which is to say, add the variables one by one, and then afterwards re-order the variables to the final order.
