The filter change is a pain in the ass on the starboard motor. The verticle filter on the starboard motor is not bad, but the horizontal filter is a majotor PITA.
As for the oil, I buy 4 pails and have a bit left over which I keep onboard.
The oil change system is great, but make sure you follow the lines out of the head unit to determine which engine is which BEFORE you use it - how do I know this and why is this prevelent??? On my boat (and yours I believe), the head with the control on it faces the opposite direction of where the arrows are pointing. Basically, the port is really the starbord and vice versa. Year one with my boat I couldnt figure out why after draining my port motor my dipstick was still showing full.
Also, on your genset there is a valve that needs to be opened before you start to pump the oil out of the genny. Its right at the bottom of the genny where the line for the oil changer comes thru.