Help with a BIG stout recipe......with lager yeast

One of the guys in my local brew club has mentioned a doing a big every year and using lager yeast to smooth it out. I want to do a few stouts this fall/winter. I would like to do a nice mellow one for the SWMBO not too far off from Guinness draft (she only drinks dark beers). I would also really like to put together a really Big stout. Lots of flavor but not overly chocolaty and with enough bittering hops to balance it out. Im thinking in the 7-8% range maybe even higher as long as it doesnt have a strong hot alc. taste. I figured the lager yeast would do a good job of smoothing it out. Ill probably do something in between at some point as well, (Guinness extra stout range?) Any suggestions or criticism for any of these. Thought it was kind of an interesting idea

Heres what Im thinking for my mid level "standard stout"

9.0 lb 2-row
.75 lb Flaked barley (would flaked oats be better? what flavor difference will there be???)
.75 lb black patent
.75 lb C 60L
.75 lb Roasted barley
1.00 oz Chinook @ 60 min
.5 oz Cascade @ 30 min

Any input? I have never used flaked oats or barley and this is my first shot at building a recipe. I want it to have solid flavor but not with an overly chocolaty or roasted flavor.

Input on a BIGer stout recipe is also appreciated. looking at something in the 1.080-1.090 range with lager yeast to smooth it out