Very Difficult indeed , so i go for a solo Mark performed during Badge at a gig with Eric Clapton in Surrey February 7, 1988 . totally mind blowing imho!!!
proof here: http://www.filedropper.com/ecftmk-badgemksolofebruary71988
I don't know this one in particular, but I don't like very much his solo on Badge on 88 tour, I prefer EC's one, because Marks keeps in D minor pentatonic scale which doesn't fit to the song imho,.
Eric is more in D7 scale (or G major scale) which fits more with the chords progression.
but of course just a matter of taste
Although i have the feeling EC is not playing a D-mixolydian scale during his solo at all ( not present in the sample) but for me it seems EC plays an A-min.blues scale and Mark a regular A-minor (aeolian) scale (both with a lot of fills).
you can hear Mark playing a little D7 arpeggio (offcourse over de D(7) ) chord and tricks it with bending the F# to a G note to continue with the A minor scale. And at other moments he seems to bend the E-note a whole to F# let it ring and it up a half note up to G without releasing the E note.
I give you the credits for the other 1988 shows... but during this particular gig he nailed it and a bit kicks EC''s ass
But heeee indeed its all theory ( i am sorry) , a good guitarist can let me cry with one touching note and a really really,good guitarist by knowing when not to play a note........the latter are hard to find.