Really like the sound of it - good review. I tend to go out 10-20+ knots with my trusty 9.0 and it sounds perfect for my size/sail/wind combination. When you're describing the planing sensation it brings to mind the phantom 300 I sailed in dahab a few years back - that seemed to glide through the gears rather than freeride on-off planing. Think my konas great but its quite physical to get it going and the 377 sounds like it'll offer a lot more in the way of future thrills ( proper railing, beating straps , and learning to use the sliding mast track compared with the fixed point on the kona).
Cheers and keep us posted!