I tow many miles...important to get the Trailer set up properly for the Boat is first priority!
Helps to spread the load evenly,and pre-empts a lot of of other problems!...
For me it's Engine down 2/3 lowered hydraulicly onto a large piece of SHAPED Softwood,to take strain off Ram...it will actually bite into wood and be VERY stable.I don't think the standard engine locks are upto the strains incurred towing long distances with a big engine!
I have the Engine turned to full lock Port and strapped with at least two ratchets and secured to trailer to stop any bounce..on a 250HPyou want it secure!
Boat is secured to trailer at front with winch and Separate ratchet strap (or safety chain)Rear large strap through towing eyes.
Check regularly on the trip!