My interest at present is discussion of the head oil leak. Is it true that the leak is likely the head plug not a head gasket. Also, would this cause an increase in upper engine clatter? Almost sounds like a loose spark plug without the backfire, or like my valves are playing marbles.

technically you have a relay, not a solenoid (the decomp is a solenoid)

check that you are getting volts from the starter button to the relay.

or quick check, push starter button,
1st click is decomp (bend over and check arm moves),
2nd click is starter relay.

no clickety click? check battery.

Ok, the problem might be your relay.

sometimes they stick, mostly closed, but sometimes open.
take a plastic handled screwdriver and strike the rear fender just below the ig switch.  That should rattle the relay enough to unstick it.

if not, take the seat off, and find a 3 wire connector and make sure it's tight.  Next check for voltage at the relay when you press the start button on the 2 small wires on top.  1's ground other should be hot when pushed.