I hear you. The problem is that there isn't absolute answer. It varies substantially on the overall dimensions of the boat and where the chines are placed. The challenge with skin on frame boats is that no two are the same and the adjustments you have made to accommodate the beam will change the performance of the boat making it impossible to say with any certainty what kind of performance gain or loss might be generated by going with a multi-chine hull.

I don't know your level of experience in kayak construction, which is also a factor. If this is a first boat, it might be prudent to go with the simpler design (easier to paddle, fewer things to go wrong) and save the multi-chine for your next build. The beauty of SOF is there is always a next boat.

Eric M.