I'm just now drinking my first two lagers, an Oktoberfest and a Vienna Lager, and they came out great (IMHO).
I would advise taking specific gravity readings to determine when to begin the diacetyl rest instead of a specific number of days. I started my rests when they were both within about 4-5 points of their expected terminal gravity. The rest lasted 3-4 days, I think, then I brought them down to about 40 deg. F., racked into kegs, then conditioned at 34 deg. F. for about 5 weeks.
By doing the diacetyl rest close to the end of fermentation, you are ensuring a complete fermentation (as well as reduction of diacetyl) before lagering, so you don't need to do a lagering at 40... just go right to 34. I only paused at 40 so I could rack into kegs.
They taste great. Will be drinking a bunch of them today at my alma mater's homecoming!
Hope this helps, even though I am not a lager expert! I read various sources, and how I conducted everything was based on my best understanding.