Re: Boat on Trailer
well, the answers that it's boat-specific are correct, but OP said he has a Regal, so I'd think what's right for any similar bow rider type hull. My guess would be long bunks or keel rollers with side bunks. Just a guess.
Boston Whaler, at least used to be for my 1964, was very specific: weight is on the keel. I have 2 3' bunks that are just there for stability; the weight is on the keel and you can almost rock the boat from bunk to bunk. PLus that means the boat lauches and retrieves easier, rolling instead of sliding, dry axle.
Carolina skiff, (I got for the first year of the J series, so at least back then), was very specific: no rollers. i think they said it would void the hull warranty but I'm not positive.
I don't recall looking into it for the starcrafts (alum); we just took them as rigged.
For any boat except the flats, it seems the keel is the strongest place. the ends of bunks or short bunks, or rollers other than the keel, put pressure points in flat surfaces. So except for the long bunks rigged like a cradle, I'd try to get weight on the keel as much as possible.