I've always let the fuel pumps run until they quiet before rolling the starter.
When the 90 has been sitting for a week or more, it's a "Mississippi-one, Mississippi-two, Mississippi-three -
aZOOM! But, after running some that day, it seems to fire anywhere between 1-2 seconds, if not before.
Ami's 91 Z, after passing through
Pete's Mystery Garage, never seems to wait more than a second - IF THAT - before TURQ MONSTER roars to life.
Worth mentioning? I had a couple backfires on my 90, back when I first got it. But, later I read here to hold the starter ON for about half a second after it starts. Since I've been letting the pumps reach pressure AND holding the starter on a tad after it fires, I've never had a backfire since, IIRC. (Now that I went and said that, just watch it sneeze and blow all the hoses off!
)