Bump up the gravity to 1.066, and that looks a lot like my mai-bock recipe.
I generally let lagers go for a month. I ferment in 6.5 gallon better bottles, and I give them a good swirl every 3 -4 days or so to re-suspend the yeast and get those extra few gravity points lower.
As far as diacetyl goes, I have been brewing lagers for 20 years and have only had it show up once. The need for a diacetyl rest is greatly overstated, about like the need for air locks. I would suggest tasting it when it looks done, and if you taste it, do the rest, if not just keg or bottle it.