I have sailed with a 4.2 which was not loaded at all. The max I could get with all trimming effort was 5,6-5,8 at 14-15 kts true
wind @ 70-80 degrees in almost flat
water. These polars a bid exgerated but not much compared to some other polars I've seen. With abid shaky sea these numbers would go down significantly because of low bridfge clearance and bulk hulls.
Cheers
Yeloya