Fast load

We have 73 databases, two dozen with hundreds of thousands to millions of
records, with lengths in the 500-byte range.  I'm planning to convert them
from Btrieve to PostgreSQL.

Of course, I want the highest reasonable speed so that the conversion can be
completed - say - in a week-end.

My initial take is to create a tab-delimited file and use this as input to
the \copy command in psql.

Another option might be to feed them directly to the back end.

I'm a C programmer, so writing the necessary programs for the conversion and
load is not a problem.

Any pointers?

Not-wanting-to-go-down-a-garden-pathingly,

Ted