Please think of the cheapest solution (HW).
I seriously think that the price of the developer hours will exceed the price of the HW involved, so only if you are talking multiple units (many probably) it makes sense minimize HW costs to the max.
So how many units are you talking about?
What do you expect to pay for the sketch & HW design?
How many hours do you think it will take to specify, design, build and test this?
I prefer that the mouister sensor will be flexable. ( spong is an option)
Can you clarify this requirement?
flexible in what sense?,
- the material it is made of,
- the range it can measure
- the voltage levels it accepts
- ...
Quality requirements is the foundation of a plan-able project.