2x4 or 2x6 bunk boards on trailer

Have a Stratos 275 Pro XL. Thinking of changing the bunks out at the end of the season. Has stock 2x4 carpeted bunks. It bugs me that all that boat is supported on narrow 2x4 wood boards and so few support points. I haven't heard of anyone having problems but it just bugs me. Was wondering if anyone on the board has changed from 2x4 to 2x6 boards? Just seems to me it would be a little additional insurance to have a heavier duty support for just a couple of dollars more for the wood. Any thoughts? Would appreciate input for or against. I am thinking about upping the size only on the bottom two bunks, and leaving the top two as 2x4.The way mine sits on the trailer it would not work to change the top two to the 2x6 because of the ribs on the bottom of the boat (or whatever they are called--you know what I mean. Only con I can think of is that it may be a little stiffer getting on and off the trailer. Thanks in advance.

You prob'ly know this already, but anyway. The boards are under compression load just at the points where they bolt to the trailer. Otherwise they are under almost no load. The weight of the boat is carried by the frame of the trailer with the load distributed through the rigid fiberglass of the hull. In some cases the wood gets slightly bent. The in-between parts of the boards are momentarily under heavier load when the hull engages them as you drive the boat on the trailer.

If the current 2x4s are still in reasonable condition, they're adequate. On the other hand, 2x6s won't hurt & should have no noticeable effect on loading.