Transporting a Malibu Two

I have a Malibu Two and a Acura MDX SUV. I transported the kayak home with foam blocks that pushed on my factory rack (only 3 feet of seperation between two bars) and strapped it down with two straps. I also had a strap from the bow carrying handle to the front of the car. I am planning to travel 250 miles to the beach on the highway. If I add a strap on the stern will this be adequate? Are there any better methods?

I always run a strap on the bow and stern and one across the belly or center.

1982 20’ MAKO w/200 Evinrude