I have explained my reasons for using ca, not that I need to justify myself and not because there is a better or alternative method.
Just a thought on this reducing tube length by 1mm or so, make sure it is only 1mm and not in danger of leaving the clip end rubbing on the belt or sticking out past it.
Some of the crap kits we use have little room for errors, also in the case of FP you could crush the nib or not seat the cap correctly by taking it down too much init?