HI,
I'm pleased you have fixed your leaks. It remains to to be seen if Riff Raff suffers from that condition.
Regarding the Trailer roller set up: I'm using the trailer that was supplied five years ago with Vagabond so the following only applies to that ype of trailer. I know that later trailers (and I don't know when the changes were made) have a different rear roller configuration.
None the less, this might help: with Vagabond (and now Riff Raff) I found that the optimum arrangement was for the rollers at the back end of the trailer to be set so that the width between the inside edges of the outer rollers was no more than 20mm greater than the width from the outside edges of the "bilge keels". That set the "bilge keels" just inside the outer rollers but not centered between the inner and outer rollers.
When recovering the boat, it all looks a bit drastic as the bows push against the low part of the U shaped rear pivoting support. That brings the rollers towards the bows and, with a bit of grunt, she will climb onto the rollers. The U shaped pivoting support now assume a more normal (upright) stance stance and the boat can be winched fully into the cradle. The winch is pretty good at keeping the boat on the centre line*. It helps if you have an assistant near the stern, armed with both a boat hook and a stern line, to provide pushing and pulling lateral guidance if required. The boat then sits nicely on the trailer.
When launching, the boat now rolls back almost too easily and you have to hang on to the bow line, other wise there can be quite a noisy clunk when the bow drops onto the middle of the U bend of the rear roller support as she leaves the bow rollers. I intend to experiment with tying a line to the bottom of the U bend to pull that forward at "just the right time".
So far this has only been used on a steepish launch and recovery ramp. I've yet to see how it will work on a shallow ramp like the one at Mylor.
* particularly if it is electrically powered. Electric powered kits, including winch, battery battery box, solar panel and remote control are available, should you want one. Mast raising adaptor as an optional extra. POA c/o Riff Raff. Delivery in 2020. E&OE etc etc