strumming slash chords

I know how slash chords are constructed & fingered, but I have two questions on how they're played.

1) I know that sometimes, in each measure, you play the bass note of the slash chord by itself, and then strum the chord after; which is 'bass strum strum'. Like in Whiter Shade Of Pale. But in such a case, during the strum strum, do you strike all the notes of the slash chord, or do you strike all except the bass note? (Or can it be done both ways - depending on the song?)

2) But if you don't see any mention of 'bass strum strum', or the tab doesn't show a seperately played bass note, can you assume that you just strum the entire slash chord at once, much like an ordinary chord?
1) you can do it both ways, depending on the song.
2) Yes.
A slash chord is simply a normal chord, which doesn't have it's root as the lowest note. Treat it the same as a normal chord.

Thanks Greybeard. Another question for anybody:

A slash chord can be an inversion, or it can have another, non-chord note added to it. But won't this sound dissonant? I suspect that by itself it might sound dissonant, but it can sound right if it's in the proper context, like a chord progression with a steadily rising or lowering bass line. Can a slash chord even have a bass note from outside the song's scale?

Yes, a slash chord can be used with a non-chord bass note, even one outside the song's scale.

Yes, this will often sound dissonant and will take more skill to work with than a normal bass note.

The longer the outside note is held, the more dissonant it will sound. Even a very dissonant note can sound good if only held briefly.