Re: longer hitch for launching boat
I think the extension will work fine by the way...
I know the tongue weight on my 25 footer (lighter than yours) pushes 500lbs. But when you combine THAT with the angle of launch, and the tongue weight actually decreases dramatically. I WILL strongly suggest you not hitch to the extension until you are ON the ramp though. Block the trailer, unhitch, slide in the extension, hitch, pull forward, unblock, then slide it in!
Make sure to remove the extension as well on the ramp... And you'll be able to use that thing for years!
I had a sliding neck on my old trailer, I think the stress is manageable.
"Rum Line" an S2 7.9 - cheap, fast, trailerable, and paid for.