Replacing Boat Bunks Questions

Have thought of a few design changes and wonder if anyone else has done similar or if they may not work well or be worth it:

Replacing the 2x4 with a 2x6 for better boat support? (boat sits on the wide side). I also wonder if it would be easier to winch the boat up on the trailer due to more surface area for support?

Using through bolts (carriage bolts with stop nuts?) instead of the lag screws? And has anyone considered using the composite lumber you can buy for decks? I'm thinking you wouldn't even need to carpet it and the boat would slide on and off very easy - maybe too easy? And of course it would last forever.

Thanks in advance for your suggestions.

I use carriage bolts, and counter sink them so the heads are below the surface of the 2X6.

The stop bolts are a good idea, for the bunks to work the must be able to move on the trailer. As the bunk flexes there will be quite a lot of movement relative to the supports on the trailer.

On last thing the bunk will twist as it conforms to the hull. To get the best fit I find it necessary to trim the edges of the bunk with a wood plane. For that reason, the composite materials may not work as well as they would seem.