Hi, I have no answer for you, but we have quite similar problem few years ago and come to conclusion not to use mysql (version < 5.x) for fulltext search because its
- horrible slow in searching
- horrible slow in indexing
- horrible inconsistent (for the same question different results in two following queries)
We have decided to use Lucene as base of our own search engine. If you cannot write your own, then you can use Solr and binding for your language to use it. Try to search solr and lucene at google. Both are projects of Apache fnd.
Good luck,
Mirek