I don't have much experience with MJ and strains, but I read quite a bit on it. It might be best to get some advice from someone that actually has experience with different strains, but I'll offer what I know.
Marijuana has two primary chemicals that affect the body: THC and CBD. Both treat inflammation, but a strain that has just as much or more CBD than THC is what you want. There's a group called CBD Crew that specializes in strains which fit this description. I've never been to a dispensary but I think they have descriptions of CBD:THC ratios on every strain. Don't take my word for it though.
As far as smoking vs. eating, I can say through experience that smoking is great for instant pain relief and increasing one's appetite, while edibles are good for actually targeting the symptoms directly, which smoking doesn't do nearly as well. However, I have read extensively on cannabis oil, which seems to be the downright most effective form for treating Crohn's and other illnesses. People have gone into remission with cannabis oil alone. There's a video on how to make it here:
http://www.youtube.com/watch?v=0sGWxz0DMSI
I personally would like to see how putting the oil in acid-resistant capsules would affect the potency...but alas, I don't have any to experiment with.
No matter what you do, if you've never ingested marijuana before, you're going to have a low tolerance to its effects, and thus you will get high very easily. It's probably best to take doses when you don't plan on doing anything, like when you get off work, or way before you go to work. I'm talking several hours. On your days off, take it whenever you'd like; I know that user FrancisK took a whole week off of work so he could self-medicate with marijuana.
Hope I helped.