Ditto to what Fonzie said (ayyyyyy)
I started with an operator that flies a fairly mixed fleet of singles and twins when I had about 1000 hours and, after proving myself on the singles, have steadily progressed onto the twins. Very few operators would happily put someone with no twin experience onto revenue carrying charter flights without some "proving" time. Be it 1000, 2000 or 5000 hours SE, as far as the operator (and insurance company) are concerned, the big 0 in the multi-engine column means a bit more.