I had this one personally, my longest wait was 4 hours, but the other two were much hsorter.I had to wait 8 hours on the cactuar NM in Altepa on the staff trials.
They don't have a set window time to spawn. Lottery spawns can appear in place of the placeholder anytime it would respawn after being killed. The only time a lotto NM can't appear is the next spawn after the NM was killed. People keep saying "spawn time is approximately X but can be as long as Y" on the wiki, and it's a load of crap. The NM simply has a set, low percent chance to appear instead of the placeholder on each spawn. There is no minimum, nor is there a maximum (sadly) time for the NM to appear.Some NMs have a painstakingly long open window time to spawn.
I spent time hunting Centurio XI for his BLM scrolls years ago, and someone said it took at least an hour to spawn and can take much more than that. The latter part is true, but I debunked the minimum spawn time when I was camping it- I went to the quicksand caves and the NM was up already (guess someone gave up just before it spawned). I killed it. Placeholder appears and I kill it, then Centurio XI pops again. There is NO minimum time. Virtually all lotto NMs follow the same rules.