How fast should I change temps on a lager yeast

Going for my first lager, will use dry S23, here are the steps and questions:
1)Pitch at 65F, wait fermentation to start
2)Drop temp to 54F
3)Let ferment to 2/3 done
4)Increase temp to 65F for D-rest
5)Leave at 65F for 3 days, then rack to secondary/lagering carboy
6)Drop temp to lager temp, about 40F
7)Lager for 3 to 4 weeks then rack to bottling carboy
8)Prime, bottle and leave at room temp

How fast should I do steps 2, 4 and 6, without issues from a stressed yeast?

10 days

Its better to chill your wort to lager temps before pitching. If you pitch at 65F and the yeast is ready to start munching, then you'll get a bunch of undesirable flavors until the wort temp drops. Just go ahead and drop it to 52-54 and then pitch.

If you do a D-rest, you can let the temps rise naturally to 65F, which should take a day or so. Leave it there for 3-7 days. Once that's done, you can cold crash immediately. The theory behind slowing dropping the yeast temps is to not shock the yeast if you are depending on them to finish up eating the diacetyl. However, with a D-rest, all that junk has been cleaned up by the yeast already, so there's no need for a slow drop.