As most (should) know, the official rules state that the distance between the competitors primes should be "no less than 1 cubit, but no more than 2 cubits".
Every year some weisenheimer brings a measuring tape to a tournament and tries to bully the officials into interpreting this as a modern metric cubit of 45.72 cm (or an "imperial" cubit of 20.24 inches, a "royal" cubit of 20.63 inches, a "sacred" cubit of ~21 inches, a "kings" cubit of ~18 inches... etc).
If you actually measure out any of the above "standardized" cubit lengths (given the variety of them they are, obviously, anything but standardized) they are not unplayable per se, but certainly are not a comfortable distance at which to play RPS. Players who try to force the issue often have trained at an exaggerated length, to gain an arbitrary edge over more-skilled opposition. At the extreme interpretation (2 sacred cubits) your players could be nearly three and a half-feet apart at which range it is quite difficult for them to play (even such gameplay basics as issuing and responding to a "call for prime" and synchronisation of throw delivery becomes complicated at that distance). It's also exponentially more difficult for the officials to penalize late throws when they can't see the entire playing field without moving their eyes.
Therefore, it's always helpful to remind players, officials, and organizers alike that the wording on distance actually pre-dates the founding of the paper scissor stone club by at least 200 years - a period where short-changing by merchants had become so rampant that a "cubit" of fabric bought at market would scarce be more than 8 modern imperial inches, and could often be considerably less, depending on the country, city, market and vendor.
As such the "book" definition of a cubit (the length of one's forearm) had little to nothing to do with the reality of the measurement that the society of the day practically dealt with.
We clearly understand from archeological record that dispite the beginning of the use of "cubit" wording in the oral "rules" that were developed ad-hoc by the upper classes, they (as we do) actually played at distances between 4 imperial inches and 12 imperial inches (which, to me would suggest that the upper classes were - as we might suspect - being targetted for excessive gouging by vendors).
In the mid-70s WRPS steering was to declare the official "RPS Cubit" to be 150 millimetres, formalizing over 400 years of defacto practice but ended up staying the motion until such time as the United States had finished adapting fully to the metric system... I think it's obvious to figure out the rest.
So to summarize: Should players (inevitably) complain about the playing distance, the offical interpretaion of the rules involves the "spirit" of the wording not newer modern "standards" which would dictate an RPS cubit being ~ 150 mm / 6 inches. Since the standard was not certified by WRPS, it's up to each individual ref or tournament organizer to rule on the "RPS cubit" that will be used for a match/tournament.
In practice, when competitors are informed they will not be able to game the rules to obtain an unfair advantage, the actual play distance rarely comes into question.