You need to do a sanity check anytime you use a sim simply to make sure you have not accidently clicked an option you don't want to use. When you simmed you rocket with a G76-4 and have an optimum delay time of 8.2 seconds, a warning should have appeared. Either it was turned off or disregarded.
Look at the Top Flight Recovery style thin mil chutes.
https://topflightrecoveryllc.homestead.com/thinmil.html The lightweight 24" is all you need. It should also withstand a +/- 5 second error (100 g) deployment delay error with out shredding.
I simply played around with Newton's laws of Motion.
g = ~32 ft/s/s
a = delta V / delta t
v = a x t, v = sqrt (2 x a x d)
d= v,average x t, d= 0.5 x a x t^2
For example if you're rocket deploy 4 seconds before or after apogee, it's vertical velocity is v = a x t = 32 ft/s/s x 4 s = 128 fps. If it takes 0.1 second to slow down to 20 fps, then the deceleration is a = delta v / delta t = (128 - 20) ft/s / 0.1 seconds = 1080 ft/s/s in G units g = a / 32 ft/s/s = ~ 34 G.
In reality, the parachute is ~ 5' long and if it open in one length, the time is 5' / 128 fps = ~ 0.04 s. In this extreme, the peak deceleration would be 128 ft/s / 0.04 s = ~3200 ft/s/s. In Gs = 3200 ft/s/s / 32 ft/s/s = 100 G load. If your rocket weights 0.75 pound, the load is 100 x 0.75 pounds = 75 pounds.
These simple checks can be done to make sure your sims make sense.
Bob