Turning an oatmeal stout into an oatmeal MILK stout?

I recently tried my hand at making an oatmeal stout (still in secondary), and it came out a little thin - the FG settled out around 1.010. The OG was also a little higher than I expect - coming out at 1.060.

I was thinking of making it less alcoholic as well as improving the body by adding some dissolved lactose sugar to the secondary. I'm thinking 4 cups water with .5-.75lbs. lactose sugar.

Right now, my hops have my crystal malts perfectly balanced - no bitterness, and very little sweetness - and there is a wonderful, lasting roasted flavor.

In your experience, how would adding lactose sugar to the secondary affect the final beer in terms of body and added sweetness? This is a 5 gallon batch.

I personally add lactose at bottling or kegging (dissolved in boiling water with priming sugar). Usually 8 oz suffices. Not sure it really adds that much to the body but does give you a perception of some sweetness.

To increase the body add some malto-dextrine to the beer. I would dissolve 4-8 oz of malto-dextrine powder in warm water (you can boil it first and then let it cool down if you like). Add this to the keg or to the beer in the bottling bucket. I usually have the priming sugar and the malto powder solution in the bottling bucket prior to adding the beer.