After the first few responses yoy probably have all the information you need... but, we did a remodel on the main bath last year and I'd always wanted the Rainforest type shower head. I found a couple of good pieces of advice.
Firstly don't attach the shower head alone to the usual wall ounted short extension. I wanted the head to emit water about mid-tub... maybe 24 inches from the wall. I found an extension made for this exact application and it's shown here:
https://www.plumbingsupply.com/supershowerheads.html
I realize this is a U.S. site, but it depicts what we've done exc ept the extension I intalled is 22 inches long. The "estucheon" mentioned in the description is a support that mounts to the ceiling and holds the weight of the arm and shower head. I think this is really important so as not to stress the short extension coming from the wall.
The shower head we used has a small slide on top, (easily reached when in the shower) and switches the shower to the pulsating "massage" setting, which is extra nice... The whole device emits the water staight down and one can easily step out of the way if required.