Don't recommend ducking. We made stage height to the highest puppeteer and then used height adjustments for shorter folks. Rubber maid stools stack together nicely. Younger puppeteers keep growing and we have a lot of puppetteer changes.  We saw a stage from another group that had ingenious adjustable legs. They had small bucket of cement with a wider PVC pipe embedded about 2 feet length.  The smaller PVC leg of stage slipped down into the wider pipe.  But here is the ingenious part, they drilled holes in both pipes every inch up the pipe.  then they used a long nail to insert in the hole to adjust the height up when they needed. The hole went all the way thru both pipes. The bucket had a handle for easy carrying and also helped to support the stage.  One person could put the stage up since the bucket held up the legs for them.  I would add felt to the bottom of the bucket to keep from scratching stage floors. They also used this type bucket pipe system to hold up props.

I've performed both standing and kneeling and though standing is easier, kneeling tends to be more practical sometimes. Never performed with chairs though because I feel it restricts my movement. You can still move around a lot kneeling, even with high energy/movement choreography.

What I would recommend building is an adjustable stage that you can use either at a kneeling or standing level. Also works great because the stage space you have at different locations can really vary. We always have shorter puppeteers use pads made of thick rigid foam for either kneeling or standing. It works much better than a stool when you strap it on because it doesn't restrict your movement as much.

Our stage (and any for teams that I have trained) is built for the taller puppeteer.  The others use risers (stand in back, kneel in front). We have a variety of risers, including wood boxes that we built, square wood step stools with padded tops, rubbermaid step stools, foam cushions, and even aerobic steps (both foam and hard plastic).  Ducking leads to a sore back, and puppets that do not look real from the audience.

We do not use stools or chairs, as we do not sit while performing.  Not sure if the sitting performers I have seen did not sit up straight or if you can't sit straight and perform, but the puppets always look like they are at weird angles, LOL.  The major complaint I've heard from sitting performers is their backs hurt.

We use a PVC stage, although an aluminium stage is adjustable if you prefer that.
Basically whatever works for you is best for you!

I agree that it makes the puppet look awkward when you have to sit down holding the puppet.  When we stand up, we don't lean forward at a 30 to 45 degree angle, but that is what we are making the puppets do.  Too many times, I've seen puppeteers resting their arms on the top of the stage with their puppet leaning over it.  I know that they want to have the puppet look at the audience and for the audience to see the puppet better, but this looks unnatural.  I've seen some adults lean forward when they communicate, but it is usually when they are raising their voices (or yelling) at someone.

This is coming from a designer and not a puppeteer, but the puppet stage I designed that is pictured in the gallery was quite low.  It was designed for an in-school travelling program promoting North Carolina's Elizabethan history and was meant to be placed in classrooms and libraries.  Therefore, we knew the kids would be most likely on the floor and very close.  The puppets would need to be low and near the audience.  There were also live actors within the world of the the theatre that interacted with the puppets.  I believe the "stage" height was only around 2 feet.  Because this was acutally a portable mini-theatre with two prosceniums, opening curtains, wings, and rear projections, the puppeteers had to be able to navigate around a lot necessary technical elements, not to mention all the jack braces and stage weights that held up the theatre. (Keep in mind the theatre wasn't so "mini."  I think the overall length was around 20 feet)  The actors performed on mechanics' dollies on their backs for the entire show.  When crossing to the stage left or right proscenium, the puppeteer would roll upstage, under the projection screen, cross left or right, roll under the other projection screen, and roll downstage for their entrance.  Did this work?  Sure did.  Was it ideal?  Not at all!  It took A LOT or tecnical rehearsals to get it right.  We spent many a rehearsal with actors almost pushing the theatre over, rolling in front of the projectors, etc.  But, finally, on a very magic day, everything clicked and it all came together.  Until that point, it was a NIGHTMARE!

That's a really gorgeous set Kyle! Great paint job (I'm always jealous of realistic sets. I wish I had that kind of painting skill)

Thank you so much, Melbourne!:)

That is just so cool!

Yes very cool! But I can certainly understand how it could have been a nightmare to get everything figured out! Too bad there isn't a way to make something that cool much simpler to set up, take down and work with! There's some money to made if someone comes up with it!!