Hello,
But according to claimed VARCHAR disk saving space, I made one test :
a).DB : 1 TABLE , 1 FIELD [CHAR(200)] PAGESIZE 8192
b).DB : 1 TABLE , 1 FIELD [VARCHAR(200)] PAGESIZE 8192
In both comes include of 1.00.000 values
'A '.
Now lets look in size of them : CHAR DB : 6.041 MB. VARCHAR DB 6,458 MB.
In both comes include of 1.000.000 values 'A
A '.
CHAR DB ~60 MB, VARCHAR DB ~66MB.
This shows that varchar uses up to 10% more of disk space.

Made selection :
select field1 from table1
group by field1
CHAR DB : ~55sec
VARCHAR : ~65sec
So varchar is only better in triming its values not to pass blanks. But
in disk saving space, or speed it is not better, but worse, i think.