I was curious enough to look into this to develop my own recipe. If I ever were to attempt to clone Spaten Oktoberfest, I think this would come really close:
5 gallons
OG=1.056
ABV=5.9%
IBU=27
SRM=11
6.5 lb German Vienna
3.5 lb German Munich II
9 oz CaraMunich
1.25 oz Hallertau Tradition (6% alpha, 60 minutes)
WLP830 or Wyeast 2206 -- either will work great!
Make a big 3-quart yeast starter a few days in advance.
Single infusion mash about 148 °F for 1 hour. Pitch and ferment at 50 F for 6 to 8 days, then raise up to 65 F for 2 days for diacetyl rest. Then lager if desired, bottle or keg as normal.
If you can't lager in the 50s, suggest trying the Wyeast 1007 altbier yeast at about 60-62 F. Find the coolest corner of your house (basement!?), then you can just place a wet t-shirt on your fermenter with a fan blowing on it gently to reduce fermentation temperature from ambient by about 5 degrees.
In any case, it should taste very good fresh, but should improve even more after 4-5 months lagering in the bottle/keg.
Enjoy.