I found a formula that allows you to calculate the SG of 1 lb of malt in 1 gal of water based on the Malt Datasheet
http://www.brewingtechniques.com/bmg/noonan.html
“Extract yield measurements: Extract (% DBFG). This acronym stands for extract yield, dry basis, fine grind, and is determined using an ASBC laboratory mash. As mentioned previously, the measurements are adjusted for a uniform 0% moisture content. The fine-grind extract percentage indicates the maximum soluble yield possible for the malt. The higher the DBFG extract, the more soluble the material and the less husk and protein. Any base malt that doesn’t give at least 78% DBFG extract is substandard.
Extract (% DBCG). Whereas DBFG is a measure of the quality of the grain itself, DBCG (extract yield, dry basis, coarse grind) gives a better indication of the degree of starch modification that the grain underwent during malting, and it more closely approximates the crush achieved in the brewhouse. The DBCG rating alerts brewers to the amount of yield they can target (see chart for acceptable ranges). In reality, however, production breweries are not as efficient as lab equipment, so DBCG values need to be reduced by 5-15% to reflect the actual yields likely to be obtained in a given brewhouse.
Brewhouse extract yield can be calculated using the following formula (all percentages are expressed as decimals for purposes of calculation):
X Brewhouse Efficiency
This calculation can be extended to give the approximate density (as °Plato or specific gravity) that a charge of malt will give to a volume of wort. The extended calculation simply multiplies the yield by a constant to arrive at °P or specific gravity (S.G.) of 1 lb of malt in 1 gal of wort:
X 11.486
X 46.214
X 46.214 = 28.1998, or S.G. 1.028.”