Normal Rain X inside and out. Works fine.
I suspect the plastic-friendly version is to lever a few extra quid from gullible wealthy motorcyclists.
According to a mate that runs http://www.k2a.co.uk/ the original Rain X has solvents in it that will cause crazing of the visor material. He uses the plastic version for the stuff they make such as outdoor display material
You can see the safety data sheets here https://www.rainx.com/safety-data-sheets/
Regular uses 7% acetone as a solvent with water and is classed as level 3 hazardous as it is flammable. Plastic safe uses propylene glycol in water as solvents and is not considered hazardous.