House rule question: Grenades and delay

[Marc]

Not a surprise, I suppose, for the veteran members of T2K forums. But, as a newbie, here is my question:
-Do you apply any kind of delay to the explosion of a grenade?
-If affirmative, what delay?
-If delayed, I suppose that you allow the character to return the grenade. Any additional control to do it? A fright check to do it?
-Any bonuses to launch a grenade with delay (making it to rebound on the floor, on a wall, etc.