Hmmmm. How long did you have your plant exposed to air prior to submerging in rooting compound or water? You do not want air to enter or it will die right away. i take my cuttings at a pretty good size. I don't think the size is your problem at all. I keep my compound as close as possible so i can get it in there asap. then i let it sit for 10 sec. then trasplant. My system is about 6" deep filled to about 3 - 31/2" of water as well. You can also cut submerged to ensure no air enters.
You need to search this forum for one of the many great videos on growing marijuana. there is a great one called: Mr Green, I grow chronic. Has a great tutorial on cloning.
if you cant find it here, PM me and i'll send it to ya.
it is comon for clones to wilt and come back. i can usually tell by the way a clone wilts wether it got air in the stem or not. they tend to shrivel and wilt. kinda a miserable clone death :doh:
yours may make it. Dont over mist them. I just hit mine at noon and evenings and sometimes imbetween. Just dont let them dry out. but dont drown them. "Mist" them.