I got this...
1. One inch isn't going to make a difference seeing as how the explosive range is actually probability and even though it will always cover a certain amount, there is a possibility it won't go any further than that point even though it normally does. As a result, giving or taking one inch won't make any difference that is noticeable.
2. If you really want to know the range, you could just use google you know... Instead of waiting an hour and a half for an answer, you could have it in 15-20 seconds tops.
3. The grenade, as shadow has already said and approved of, is fine as it is, so don't fret. You're approved.
4. For your real answer, the lethality range of a grenade is about 2m and the full explosive range is about 15m. In application to this grenade, 2m would coat the target and 15m would sprinkle the target. However lethal it actually is is primarily up to your opponent, seeing as how they decide whether or not it is really close or really far within reason. It is good to remember that though. 0-2m lethal, 2-6m major, 6-15m minor or something like that. It is really up for interpretation with a chemical grenade.