Hi there it is probably the valve oil stem seals the engine runs very hot and cooks the seals till they are rock hard. If you replace them i would think about fitting an oil cooler [ any Honda cb 750, 500 sohc will fit]. In England although the weather is probably cooler many of us have fitted oil coolers it helps steady the tick over aswell.
The oil leaks you desrcibe sound similar to ones i have fixed on my own 900 sei. i have replaced the sprocket.gear leaver,neutral switch oil seal with Viton seals these work to a higher temperature than the origional seals. I have also replaced the O rings on the oil pump and pressure release valve, this has stopped the drips of oil.
The roads sound good where you are ! our roads are very crowded these days Scotland is the last frontier for clear roads.
Hope this helps