Hi Martin,
welcome to the club of waarschippers. We applaud your effort of rescuing a 570 from a painfull and horrible death and use it for fun and pleasure.
The screws are have been a problem for the boats that are built in the late deventies and early eightys. Before that they uses copper or "messing", after that period they switched to stainless steel. I have had that same problem with my 730 (and other boatowners) and there are different solutions to that problem. Steef Ton has a perfect solution, if you are looking for a quick one maybe you will try mine.
I drilled out all the polyesterfiller that was capping up the screws. then I cleaned the screwheds from rust with a mecanical tool from Dremel. Afterwards I filled the hole with epoxyfiller with a thickener, after I sealed it with clear epoxy. Maybe not the ultimate solution but time will tell.
For as colouring concerns, the sides of the coachroof should be varnished, as wel as the front and the back. Furtermore the toerail, the wood beneath the rails of the sliding hatch, as the wood at the front of the footwell. The roof and sliding hatch are mostly white. The colour you use for the sides of the boat should match the colour inside the footwell apart of the places were you should have uses varnish.
good luck.
Hedzer
