Everyone seems to have settled on KYOCERA solar panels at the 135 watt size and then many are using the FlexCharge NC25A controller because it is so simple. As for mounting over the davits, this can be done with a KATOMARINE.com system where the panel mounts onto a raised arm that is bolted to teh davit stabilizer bar. You can see pictures of that in the photo albums from the Maine 2011 rendezvous I just uploaded, here is a copy...
Flex Charge NC25A
www.flexcharge.com/flexcharge_usa/products/nc25a/nc25a.htm
Photo of KATOMARINE mount
Hayden on anchor in Maine