does the length of a varchar change performance a lot?
I'm not sure if I should have 2 diifferent tables,
one for
pkey | num.value | varchar(50)
and one for
pkey | num.value | varchar(2200)

or if I should only use the last one.

Do I gain any performance if I split them up into two tables?

The answer may depend on your DBMS. For Oracle, it would make no difference, as a VARCHAR only uses as much storage as it requires for the value it contains.