Diacetyl rest, or no, and when?

I'm relatively new to brewing true lagers, and I've had some "issues" with previous batches. I'd like to see my current batch ferment out as intended.

It's a Munich Dunkel, OG 1.055, pitched with 1 liter of WLP 838 South German Lager starter (prepared with a stir plate) at 70 deg F. Wort was well aerated with an aeration stone and aquarium pump before pitching. After 12 hours, a decent kraeusen was going, so I put it in the beer-fridge and gradually turned the temp down to 52 deg. White Labs website says optimum temp for 838 is 50-55. After 24 hours at 52 deg, it's still rolling along, so I think I'm good so far.

I'm planning on transferring to a secondary fermenter when the high kraeusen subsides.

My questions:
1. Should I conduct a diacetyl rest? WL website says 838 is low in diacetyl byproducts, and several reviews on their site say a rest is unnecessary. But it wouldn't hurt, would it?

2. If conducted, when should I do the rest? Before racking to the secondary? After? Immediately before lagering?

3. At what point does secondary fermentation end and lagering begin? When I've reached FG? When FG is no longer dropping, just turn down the fridge to 35 deg, or do I need to rack it off the yeast again?

4. Should I bottle it and THEN lager it, to ensure adequate carbonation? If I lager it for an extended period at very low temps, won't I risk having too little yeast in suspension to condition it when I bottle, if I lager before bottling?

Enquiring minds want to know. Thanks in advance for sharing your wisdom.

I would taste the beer post-ferment and decide at that point if a diacetyl rest is necessary. If there's no detectable diacetyl, I see no reason to do a diacetyl rest. Diacetyl rests usually involve warming the beer up to 55-65* for a day or more. The colder you keep your beer, the more haze and flavor stable it will be, and if there are any low-level infections, that will preserve the beer from them. So if you don't have a good reason to warm up the beer, don't.

To paraphrase Noonan: For dextrinous beers (such as your Dunkel) if the reduction of density has slowed and is about 1/3rd the value of the OG, then is should be fermented in the secondary between 33-41*F for at least 14 days. Lagering is a post-fermentive rest, so it should conducted after fermentation is completed. Dextrinous beer should be lagered for 7-12 days at 33* for each 2* Plato (1.008) of the OG. So Noonan would recommend 48-82 days for your beer.

As for yeast, I've lagered and fined beers, and still had enough yeast in suspension to carb up the bottles. If you're worried about it, you can bottle with speise (wort) and active yeast. Basically make a yeast starter, and once the yeast goes to work, mix that in with the beer to carb it.

I would say if you pitched at 70 degrees, and then reduced the temp to optimum fermentation temperatures, that a diacetyl rest is mandatory.

I don't always do a diacetyl rest, but that is when I pitch an appropriate (HUGE) starter, and pitch at 45 degrees.

The diacetyl rest is done immediately at the end of primary, when the SG is about 75% of the way to FG. After the FG is reached, the beer is racked and the lagering can begin.