equipment for sPL iMs >1?

For the straddle planche iMs after level 1, can those be done using an exercise ball? I hope so because I'm not sure where else I could do them.

Seems like a ball won't have a sharp enough edge. Where do you train? At home: a chair or a table. At the gym: a bench.

I don't have a table that would work. A pair of chairs facing each other might work. I have long legs, I'll have to try it.

I use a piano bench for pe2 im.

Use the arm of a couch.  It's the right height and readily available.  

I used an exercise ball for IM2 and it worked well. I sat in on top of my jump box so I could lean over and hold onto something, and had heaps of room for my legs.