optimizing table size, is it worth it?

[Cartoper]

I am new both my employeer and Interbase. We are using Interbase 7, I
have heard reports that as the database grows in size (300M to 400M),
preformance really takes a hit. I am currenting adding a whole new
feature to the application, so I will be adding a bunch of new
tables.

I am wondering... Is it worth while to optimize tables to fit into
pages? My thought is that if you had a simple table:

id integer
name char(10)

Rather than leave the name at 10 char's, round it up to 12 so the
table is 16 bytes and will fit into a sector nicely. The only catch
is that all the tables will have varchar's of lengths over 50 most of
the time. Would that null and void such an optimization or not? Here
is an example:

id integer
name char(40)
desc varchar(60)

My thought is that by rounding the desc up to 84, that will make the
table max out at 128 bytes, and again always fit nicely into a page.

Also, does placement of varchar's have a large impact on preformance?
In all my tables, there is a updatedby, updateon, insertedby, and
insertedon field. Should these fixed length fields always come before
variable length fields or will the engine do that automatically?

Are there things I should be keeping in mind as I create new tables to
help preformance?

Cartoper