In my experience the vacuum pump through dipstick hole will always be second best in terms of extracting oil and any attendant sludge should there be any.
I have a Merry Fisher 805 fast fisher with a lovely Volvo TAMD 200hp 6 cylinder which can only be vacuum pumped as the french makers Jeanneau skimped by not fitting a simple manual sump pump and access to the drain plug in the bilge is not possible. I know from dropping oil from my two classics just how much crud can flow out when a hot sump of oil is allowed to just gush out when the plug is withdrawn.
Nevertheless with the VEA engine not even a vacuum pump is an option. I wonder why
