Best way to indicate L.H over in piano

Question

I have piano sheet music that has this:

But I wanted to change the right hand clef to be lower to get rid of all the ledger lines:

But then I realized I could put the left hand over part on the bottom staff like this:

I am just wondering:

1. what is the most common thing to do in a situation like this?
2. Is it too jarring changing the clef and back so quickly and in the middle of a measure?
3. Is it really necessary to write "L.H. over" or something like that? (If so, what is the best thing to write?). Or should the pianist "just know"?

Answer 1

TL;DR

Sample 3 is the way to go. It's fine to change clefs, and no "over" indication is needed. This is clearly illustrated in a passage from Beethoven's "Pathetique" sonata (Op. 13, mm. 49–56). The right hand repeatedly crosses over the left, indicated only by clef changes in the right-hand part.

(Image source: IMSLP)

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1. What is the most common thing to do in a situation like this?

For a single note/chord, it can be written as in the third example. In the below passage from Debussy's "Le Petite Negre" (mm. 6–11) the hand-crossing (mm. 9–11) is given no explicit indication, but is clear to the pianist.

(Image source: IMSLP)

2. Is it too jarring changing the clef and back so quickly and in the middle of a measure?

Not at all. This is quite common. Chopin does this at the end of his etude in Gb major, Op. 10 No. 5. For the penultimate chord, the left hand jumps to the treble clef, then back to the bass clef.

(Image source: IMSLP)

3. Is it really necessary to write "L.H. over" or something like that? (If so, what is the best thing to write?). Or should the pianist "just know"?

It's not necessary to give an explicit indication (the above Debussy, for example). However, it is sometimes done when the extra clarity is needed. The below image is the final measure of Serge Bortkiewicz's Prelude III in E major (Op. 40, 1931, first edition)

(Image source: IMSLP)

The left hand starts the arpeggiation from the bass staff, the right hand takes over in the treble staff, but the left hand then crosses over the right to play the final note of the arpeggio. "M.S." (mano sinestro) is the Italian abbreviation for "Left Hand", and reinforces the use of stem direction as clarification of how the arpeggio should be played.

Other options for hand-crossing

Third staff

When the hand-crossing is extensive, it can be easier to read by adding a third staff. Liszt's etude "Un Sospiro" does this, along with stem direction to indicate which hand should play the given note. Measure 3 and 4 are shown here.

(Image source: IMSLP)

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A related notation is discussed in What does the L-shaped symbol attached to C5 and G4 on the top staff mean?. In this case the notation indicates when the left or right hand should play a note that would otherwise be understood as played with the other.

Answer 2

Of the solutions you suggest the third solution is the best, particularly as it makes it clear that you want a half note. There are other, even better solutions (see the answer by @ElementsinSpace). No pianist would have any trouble understanding what you mean. There's absolutely no need to add "over" and "L.H." is probably superfluous as well.

Answer 3

Firstly, piano players would much prefer an 8va/8vb (even over a long stretch) to an octave clef. Octave clefs are not for piano.
However, that octave of Cs in the bass is not too many leger lines to be written without an 8vb, as the interval of an octave is quite recognisable. (see some of the examples in this post)

So your third option would be fine if you got rid of the octave clef – either have 5 leger lines below the lower staff, or use 8vb.

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When necessary, left and right hands are often indicated (in french) with m. g. (main gauche) and m. d. (main droite) respectively. Though in english LH / RH would be fine (but you don't need the word "over"). Another option is to use the symbols └ & ┌.

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Each hand usually sticks to a stave of its own, but it is sometimes okay to move one hand's voice across staves (and I think it makes sense for this passage).

My proposal is below, but it is hard to tell if this would work for the rest of the piece.
Note the position of the rest.