Would it be easier to use an oil sucker on those? You can buy a hand-pump that has a little hose you can stick down the dipstick hole, I use one on my inboard boat, and we use them on all kinds of inboard and outboard boat motors... it's pretty easy and clean, and saves a lot of trouble trying to get to the drain...
This is one kind, but they make them with self-contained reservoirs, too:
PUMP LITTLE PAL MULTI- PURPOSE HAND PUMP PAR 120370