answer

Is it possible to use magnets to temporarily fix the sensor head?
If so, are there any recommendations for magnets?

Answer

Magnets can be used.
Let it stick to the metal at the bottom of the sensor head.
Generally, if the target is large, such as a machine tool, we recommend a magnet with a strong attraction force.

Case of strong adsorption

Reference item (example): Neodymium magnet square type length 40.0mm x width 8.0mm x thickness 5.0mm
Finish: Ni plating
Magnetic flux density: 308mT
Adsorption force: 8.1kgf
Limit operating temperature: 80 degree celsius
Use 2 pieces (NeoMag)