Ballade for viola and piano

Here my new piece for viola and piano. 

Harmony is quite simple and diatonic in EbM with any modulation at all, just a few A natural borrowed, I guess, from Eb Lydian scale. 

Harmonic progression

EbM - EbM - Gm - Gm (x6)

AbM - AbM - EbM - EbM (x4) 

Gm - Cm - Fm - BbM (x2) - BbM - BbM

This progression is repieted exactly the same and finish with a few bars in EbM. 

Why do you give the piano proper sixteenth notes but the viola you give the double line "tremolo"? In my many years of playing a string instrument, I've never seen 1 or 2 beamed tremolos unless the music was decently fast-paced. 

Hi, to be honest, I used that notation because I have never used before, that`s it. And I have seen it many times on classical music scores...anyway, thanks for the comment. I`ll correct it :)