Isola Bella ferry pre-book?

Greetings. We are staying in Stresa in four weeks. I want to tour the Borromean islands on day 2. I have seen many “ off on” skip the line trips offered here on TA. Is it a good idea to book ahead? Do they use the regular ferry from Stresa? I want to leave very early. I have been reading horror stories about ferry lines on Lake Como..I’d like to be well prepared! Thank you