How much nitrous for a stock piston?

I will add this, back in the day (80s), i would T off & run a mech. parts house fuel pump on my 360 dart sport, ran the good old 125 power shot system, never pulled timing, no heater, no anything, just the kit, with that 125 hit (god knows what the bottle pressure was at), i dropped a solid 3/4 & 7-8 MPH on ET, i thought that was good (this was back in south fla), fast forward to my 97 6sp. Z28, i decided its time to do it right, i found a good used NX 300 hit kit for 400.00, it had everything, purge, new NX heater, blow-down tube, big noids, you name it, i ran a 100 shot to start off slow, got a window switch, max timing was 28* (4* pulled) from factory tuned setting through the computer, off the bottle it ran 13.4/13.5 @ 100/101 on 2.00 60fts. consistantly, on the bottle, after my 3rd. pass (working on the launch), it ran a 12.01 @ 115 on a 1.81 60ft., there was an 11.8 in it i'm sure, so this is why its very important to do this stuff right the 1st. time & keep everything in tune, i dropped almost 1.5 seconds & 15 MPH on just a meesely 100 shot, bottle pressure was at 950 in the lanes, had the window switch set for 3000 (on), 5600 (off), shifted at 6000 (so it wasn't always on the nitrous through the run), launched on that 12.01 pass at 2500 & it got into the nitrous early.

oh, get a purge kit too.