tsvector limitations

Dear list,

How big of a file would one need to fill the 1MB limit of a tsvector?
Reading
http://www.postgresql.org/docs/9.0/static/textsearch-limitations.html seems
to hint that filling a tsvector is improbable.

Is there an easy way of query the bytes of a tsvector?
something like length(tsvector) but bytes(tsvector).

If there no easy method to query the bytes of a tsvector
I realize the answer is highly dependent on the contents of the file, so
here are 2 random examples:
How many bytes of a tsvector would a 32MB ascii english unique word list
make?
How many bytes of a tsvector would something like "The Lord of the
Rings.txt" make?

If this limitation is ever hit is there a common practice for using more
than one tsvector?
Using a separate "one to many" table seems like an obvious solution piece,
but I would not know how to detect or calculate how much text to give each
tsvector.
Assuming tsvectors can't be linked maybe they would need some overlap.

Thanks in advance.