>>52863117Of course it's not guaranteed, it's probability. The issue with R/S/E specifically is that the rng is frozen, unless in R/S's case where the battery is working. All shiny frames are the exact same, meaning run away encounters or rng abuse is the only way to hunt in these games. FRLG do not have this problem however, which you should take advantage of wherever you can, like I did for Deoxys in pic rel.
>>52863163Depends on how long it takes to encounter, run from, walk to the door and back to Rayquaza. Maybe around 30 seconds? Keep in mind, in R/S, Rayquaza does not reappear if you run away, so you have to do it in Emerald (Or have a working battery in R/S for soft reset), and therefore you have to do run away encounters.