My Wooldridge came with the bunk trailer. I don't have problems launching or loading it. I try to keep the upper third of the bunks out of the water when loading.

I've thought about the plastic slides, but haven't found that I need them. West Marine sells a product called "Liquid Rollers" that might be useful for you.

I think you get better support for the hull and you don't have to worry about broken rollers causing hull damage. If you have rollers, more is better for weight displacement.