I've been able to put grand pianos (without reproducers, but this would
probably work for them, too) on their side by myself many times, without
lifting any weight.  Here's how I do it:

Place a sturdy chair, or the piano bench, or a jack stand, or whatever
else you can improvise next to the front leg of the piano's straight
side.  Stack telephone books or whatever you need, until you have a
support about 3 to 4 inches higher than the underside of the piano.

Then use an automobile jack placed on top of a crate or whatever you need
to get it to the right height so you can jack the piano up so that only
the left front leg is off the floor, just enough so you have room to
unbolt and remove it.  But before you do, slide your chair and telephone
books under the keybed or behind the leg; wherever it will go without
damaging the piano or reproducing mechanism.

After you've removed the left front leg and the lyre, you can lower the
left front corner of the piano onto a heavy mover's pad or your dolly,
tilt the piano up so it is standing on its side, and remove the other two
legs.  If you lower it onto a dolly, you'll of course have to brace the
wheels so it doesn't slide out.  To set the piano up you just reverse the
entire process.

Larry Lobel