Tchaikovsky + Bach?
I had a general question regarding Presto from Bach's sonata 1 in G minor and Tchaikovsky's D Major Violin Concerto SECOND Movement. What does one need to have played before these pieces and what would you rank them out of 20? 1 being very easy and 20 being the most difficult.
The numerical rankings will be useless information. What you should have played in preparation is very useful -- my opinion as an amateur.
Those pieces you want to play are a 6.5 give or take. Everything Paul suggested makes sense. You've certainly done Bach A minor, Thais, several Bach solo movements if not the whole E major or equivalent, and a few other sonatas or show pieces. Maybe another concerto too like Lalo or Mozart.
The Canzonetta *is* much harder than Thais, but if you choose to play it with naive fingerings, the difficulty level is much reduced.
The Presto from Sonata 1 is tricky but not overwhelming. It depends what level you want to play it at but as a minimum I would suggest that before attempting it at all, you should be very comfortable with some of the the earlier Kreutzer studies (e.g. no.2 for moto perpetuo playing and no. 13 I think for string crossings - obviously, you need to get your fingers down in the right place quickly, and you need very good string-crossing technique, for the Presto to not sound a mess).