After reading all of these replies, where to begin?

First of all to those who claim that one should never use a PLAN
clause. My experience has shown that in many instances the use of a
PLAN clause can make a significant difference to the performance of
certain queries. I certainly don't use PLAN clauses on every query
but when I use them I NEED THEM. Besides, I got the original idea for
using PLAN clauses from this support list.

As for using FB1.5 specific features like naming the indices in the
constraint clause that still causes me a problem because my app has to
continue to work for customers that are running older versions of
Interbase so this is not an option. And before you suggest it, some
of them can't upgrade because they are running an OS that Firebird no
longer supports, like SCO and AIX.

Any other suggestions are appreciated.