I can see your logic and i can see Fribbtastic’s objections. I am not sure immerse in a liquid a suction cup will be necessary. I would start out with a 20mm cube. A pure flat surface right in the middle of the filament where you’re going to get the most flex of the film.

I would sincerely consider giving your film 50% slack for eventual failure and loosening but your idea is sound. I do think commenter is right though that this would be something to redo on every single film replacement AND every single resin you use.

I’d genuinely be curious to see time saved VS used up to dial it in.