Inherits is not encouraged?

Good morning,

I have two questions about inherits under postgreSQL 8.0.15.


(1) Is possible that I could change the column of a table that is 
defined by Inherits?

e.g., t1(col1, col2, col3); create table tx(colx) Inherits (t1)
I'd like to get tx shown as (col1, colx, col2, col3).


(2) Logically, I have a table inherited from two other tables, but no 
more other columns. Will it not be encouraged to do so?

e.g., t1 (col1... coln)     t2 (col1... coln)
     create t3() Inherits (t1, t2) without OID


Thanks a lot!
Lu Ying