In order to meet FIS-specifications, the beams have to be thight, regardless of brand.
Size of beam is a part of FIS rules, and homologation. (timing booklet, p 26).
An 8 mm object moving with a speed of 10 km/h is not allowed to trigger the photocell (measured at a distance of 2 m from lens of the receiver). A 100 mm object moving with a speed of 200 km/h must trigger the photocell (measured at a distance of 2 m from lens of the receiver).
The distance at finish is flexible in exceptional cases:
FIS Alpine Joint regulations:
615.2 The Finish Line and its Markings
"In Downhill and Super-G races, the finish must be no less than 15 metres wide and in Slalom and Giant Slalom no less than 10 metres wide. In exceptional cases, the Jury may decrease this distance on the spot for technical reasons or because of the terrain. "
Snow closing the photcells is such an "exceptional case". Organizers and TDs are eager to finish races if they can provide fair conditions for the racers. Visibilty for racers, gate-to-gate is the main safety concern. The distance of the finish line is not a concern under such circumstances.
This applies only to SL-races. No TD would accept scored GS, SG and DH under such conditions.
I have been down to 5 meter distance on the finish line at a SL FIS-race. However, the race was cancelled due to visibility for the athletes on course.
If you are not able to serve stable photocells at a 10m distance, just and fair conditions for athletes are most likely not present on the course.
If you experience cluttering at the photocells, ask the TD for permisson to reduce the distance at finish. "No timing - no race" is lingo acceptable to most TDs.
Mouse: Batteries in photocells provides you redundancy when powered from cable.