I may be able to make further comments when you upload the audio, but for now there are some issues I can see immediately:
Your title is confusing - is this the arrangement for violin? It still says on the music 'Viola Concerto No.1' and 'Solo Viola' but the solo part is clearly for violin as it is written in treble clef and in the violin's range. You need to make this clear.
Do you play the piano? If so, I would be very intrigued to watch you perform passages such as bars 13-16 after the first Moderato (please use bars numbers in your scores - it makes it much simpler to identify a particular place in the music when reviewing) which at my estimation would require the pianist to have at least twelve fingers on their right hand alone! If these chords are arpeggiated (the only conceivable way of performing them) you should indicate this with a wavy line.
The violin part looks mostly alright, most the chords are playable by a good performer (some, like on page 4, are not) and makes full use of its range. The trill marking on page 9 makes no sense above what notes you have written. I think you intend each quaver to be trilled with the grace note, in which case you need seperate trill lines for each one.
Finally, although this is a bit speculative, the idea of transposing up a fifth to fit a different solo string instrument has both pros and cons. On the plus side, it means that the use of open strings are the same on the two instruments, so chords will still be playable and the music is easy to trascribe via ctrl+c, ctrl+v, Transpose. The violin and viola are also similar enough to allow this. On the other hand, the orchestral/piano parts may encounter problems. Notes that were comfortably in range for certain instruments (oboes, horns, contrabasses) may now be scarily high or even impossible to produce. Certain registral characteristics may also be lost, for example the powerful timbre of low oboes or low cellos, or made insecure in a higher position (horns, strings). I'd need to see the orchestral score of this version to fully comment on this though.