[Dragsinger]

SSDiv6,

In my case I would either have a helper or take belt off and run pump with a drill.

Also, in the case of someone using a mechanical pump mounted with the original bolt holes, a helper could be in car a start engine for a few seconds to take a sample.

Doing the above would be safest with an extension on the drain valve to move any possible fuel splash away from under hood problems.

Considering the two above examples, the most safe would be the belt drive pump run with a drill with engine off.