Another interested party here - I chickened out earlier this year, after circumnavigating Mull. There was a wicked swell, although fairly light winds by the time I approached the Western entrance. A lack of local knowledge and a big warning in the pilot "Beware - light winds but a large westerly swell can lead to a false impression of conditions within the Corryvreckan" caused me to prudently go north of Scarba. Running back down the eastern side to Crinan, a small (5m?) RIB and a yacht popped out ahead of me. Made me feel really inadequate!
Seafari operate through the Corryvreckan throughout the summer in 9m Ribcraft and I'm sure they would be willing to impart some of their local knowledge.