Don't feel bad if your juniper doesn't make it.... my roommate asked me what happened to one of my junipers and got a "it died" as an answer! I thought I had it acclimated enough to put it on the west side of my house and apparently not.... but, it took 3 weeks to show the stress-too late! I've been told they are tempermental at times. You wouldn't think so by how many are planted in the medians around here, but then I found out they just plant a new one when one dies (notice, not "if"!).
If you've got the space, it's a good idea to have several trees-don't have to all be "bonsai", but just something to distract you from babying one tree to death (literally sometimes)
. I'd have a lot more dead trees if I didn't have a bunch of cuttings to "play" with!
Good luck!