I have a Coronado 35 ketch as well.
From the literature I read, there seems to be no good reason to
rig a boat of that size as a ketch, and frankly speaking, I do not see much of performance improvement, if the mizzen is up. As a rule of thumb, the mizzen should be sheeted a little closer than the main.
I love the looks of the ketch; the real performance advantage, however, will come only, when one day I will
rig a mizzen staysail.
The advantage I see already now: when the wind is piping up, I just drop the main, and have a balanced
rig with
jib/genoa and mizzen.
I would love to see further comments, my experience with the ketch
rig is limited as well.