How often supposedly Ryder's Picador and Big Smoke's Glendale to spawn?

[Super Shizuku]

I'm not sure about this, but is it true that those two vehicles will never spawn once the traitors are dead during a mission where the player has to kill them (one of them in a mission)? Does Sweet's Greenwood suppose to spawn at the same time as Ryder's Picador? I just started another 100% playthrough after almost 2 years of not playing GTA SA for nostalgia and I don't plan to lose my chance again to be able to store these vehicles in any of my garages. 

[inadequate]

Sweet's Greenwood and Ryder's Picador spawns all of the time, even after 100% game completion. And about Big Smoke's Glendale never spawns outside of the missions where it appears.

Edited February 18, 2019 by Inadequate

[Super Shizuku]

Okay, but in my old save, only Greenwood alone would spawn after I go out very far from Ganton. I think the last time I saw Picador spawned was in my newest savegame before "Home Invasion" gets unlocked.

Edited February 19, 2019 by Light Syde Riandy

[god speed]

According to the SA Special Vehicle Guide, Ryder's Picador won't spawn if House Party is passed before Catalyst.

Sweet's Greenwood should always spawn.

[lil weasel]

Most generally speaking,

Respawns occur after three minutes from leaving the area or line of sight ... depending.