Double grace notes in Chopin Nocturne in C#minor

[pianos1]

In Chopin Nocturne in C#minor, measure 9, there are two sixteenth grace notes C# and D# before a main note D# marked "tr".  Underneath the D# melody note is a G# LH bass note, followed by more arpeggio notes.

Dolmetsch says mid-nineteenth century appoggiaturas were played before the beat.  Does this mean that the C# and D# and the LH bass note G# are all played before the beat?

Is playing the D# melody note and the G# bass note on the beat and after the grace notes a possibility?

Is Dolmetsch wrong on the before-the-beat placement of the grace notes? 

How fast should the grace notes be played?

[pianowolfi]

In my book Dolmetsch is clearly wrong, as Chopin died one year before midth 19th century 

On a more serious note, the Paderewski edition quotes some handwritten marks by Chopin, according to which he wanted such apoggiaturas to be played on the beat. And I mostly follow this rule, especially in the finale of the third Ballade, where it doesn't make sense to play those powerful arpeggios before the beat. Also in this nocturne I play them on the beat, together with the bass G#.

[pianos1]

Thanks for your answer.  It makes sense.

As far as "mid-century", this means approximately the years 33-65, or the middle third of a century.  Mid 19th century includes 1835-49, Chopin's prime composing years.

Nonetheless, the scholarly edition you quoted is the perhaps the best indicator.