Iím at the point of under slab rough in and looking for some advice before we pour the house slab.

Iím wanting to construct a curbless shower stall (54Ēx36Ē) and wondering what my best approach would be. The finishing in the bathroom will be the acid etched concrete slab with a tiled shower area. Is it common and would it make sense to recess the concrete in the shower area by X inches to accommodate a shower floor system like Kerdi Pan etc.? If so, what should X be.

I can also see a time in the future where someone might want to convert this space to a bathtub/shower but jackhammering up the floor would be ill advised since it will have radiant heat pex embedded in it.

So the next question is where/how should locate the shower drain such that, at some time in the future one could easily utilize the existing drain for a tub. I guess Iím looking for a rough in procedure that would be suitable for both. A linear shower drain would also be nice but that might complicate things and itís probably outside of my snack bracket.

Thanks in advance.