Sure, why not. It will still be beer.
Corn sugar brings no flavor to the party. LGS might bring some subtle flavors of its own.
My guess is the it would be roughly like the substation ratio of DMW to LME which is, I if I recall now that DME ~44 ppg and LME is ~36 ppg. If your off a few gravity points it's really not a problem.
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Steve in St Cloud, MN
Long Winter's Nap Barleywine
6 Jolly Fellows Porter
Cream of Three Crops Cream Ale
Jolly Pumpkin Bam Biere clone - sort of
Tap 1 - Tripel
Tap 2 - American Wheat
Tap 3 - House Mild
Tap 4 - Black IPA - from Lucid Brewery wort
Bottles - Long Winters Nap Barley Wine - 2012 & 2013, & some odds and ends
In the bullpen: