Question: I looked at the sheet music for a piano transcription of The Four Seasons and I see in the third movement of Summer, 2 things that I don't know if I can do. It has partly to do with the Presto tempo but that alone isn't the issue. Here are the 2 things I see.

Alternating between right hand and left hand octave with 1 note shared(the middle note). This I'm pretty sure I can't do at a fast tempo. The middle note would probably not sound out. But I have a few alternatives.

1. I could have the left hand do an octave tremolo while I have the right hand playing the upper note at half the note speed of the tremolo
2. I could have both hands play static octaves and just play the right hand of the beginning section 8va
3. I could get rid of the static octaves all together and use octave tremolos instead, playing the right hand 8va. I tend to get less tension at a fast tempo with tremolos than with static octaves

But there is another issue I see, scales being played so fast I am essentially doing a fingered glissando. I don't often do glissandos anyway but I have never done scales at Presto before. It seems very intimidating. And while I do have fast, nimble, and strong fingers, I'm not sure how I would go about playing a scale at Presto. Would I just speed up a scale played at Allegro gradually to Presto or what?

**So how would I play a scale at Presto and which of the 3 alternatives do you think is best to get that same richness and fast octaves sound without having the right hand and left hand share a note in the octaves?**

Answer: 
Take a look at other piano versions. On IMSLP there are two piano versions:

<https://imslp.org/wiki/Violin_Concerto_in_G_minor%2C_RV_315_(Vivaldi%2C_Antonio)>

Scroll down to "Sheet Music" and click on "Arrangements and Transcriptions (13)".
There you will find two piano versions, one made by Justin Bird and one made by Roberto Novegno. They are very different. Those versions can give you great ideas on what you can do in order to play "Summer" on piano.

Also compare with the original score.

The main point is playing something which reflects the music and at the same time fits the instrument.
Technique is literally in your head. When you practice, your brain hard wires your movement into "muscle memory" and like it or not, flawed or not, that is what your brain will regurgitate to your hands until you re-wire those movements. 

If you have difficulty with speed, your technique is flawed. NO AMOUNT OF PRACTICE WILL FIX THAT. Practice doesn't make perfect, perfect practice makes perfect. 

You need to find a new teacher who can teach you proper ergonomic movement.