struct parameterless constructor

[Brother Bill]

I feel like I am going into the hornet's nest with this 
discussion.

I have created a struct with some members, and want to have a 
parameterless constructor that sets the member values at run time.

I have seen things like @disable this();  and static opCall(), 
but don't quite understand them.

How does one do this, and what are the ramifications of doing so?
Or should one just leave the parameterless constructor as is?