In Violin 3 & 4, in measures 12 through 18, the sheets say use pizzicato.  I just assumed that the similar passages 23 through 29 for these parts is also pizzicato.  But I watched Pierre's demo videos and see that they are played there with the bow, and indeed, there are no instructions there to play them pizzicato for those measures on the sheets.

Is this optional?  Can we play 23 through 29 on Violin 3 & 4 with pizzicato?  It's kind of fun to play that way.

Let me add that the current deadline will work for me and working on this project has done a lot to accelerate my learning.  I'm actually applying vibrato in some places, something I'd never thought I'd do three months ago.  Especially satisfying was learning the passages like 8 though 11 in Violin 4.  I'm finally getting them down and for a while they looked impossible.