Width of custom fields seems to be random

Hi all
I have a small issue concerning the width of custom fields: sometime rectangles containing long strings are smaller than those containing short strings and viceversa.
Additionally, fields of the same type (both reference to the same element, both varchar of the same lenghts,...) have different width.

I copy here some examples:

Departamento and Area are both refernce fields to idOrganisation. However one is much bigger than the other one, and the text in the second one is cut.

Currency-change is of type decimal(7,2), the one next to it is of type decimal(20,2). However it is much smaller than the previous one.
 

Is there a way to set the width?
Thank you very much,

Silvia

Thank you very much for your answer.
I understand that there is not a manual way to define the desired lenght and that's a pity as sometimes, fields are unreadable.
Do you think is it possible to propose it as an evolution (and funding it eventually)?
For instance, I understand that xxxxAmount should be an amount, but if the amount is millions, part of the number is unreadable and even if increasing the size of the number to decimal(9,2).

Thanks again,
Silvia