I have a few questions about dme. I want to make a light wheat beer but the wheat lme at my shop is dark. So I have 3.3 lbs of a light beer lme and 1 lb of Bavarian wheat dme. I was planning on making the wort with a combination of the two but don't know how much of each I should use. I only have a 3 gallon carboy. Also can I use the dme instead of sugar for a primer when it's ready to bottle?
(1) Yes, you can use a mix of DME and LME in your recipe, but it will affect your recipe. You would be better off using all Bavarian wheat DME. The classic recipe book, Brewing Classic Styles, calls for an American Wheat Ale, for example, to be made from 100% wheat LME having a color of 4°L on the Lovibond scale. Using less wheat will de-emphasize the "wheatiness" of the beer, and I would hesitate to use less than 50% wheat for a true wheat ale. You should use brewing software to determine your recipe. As a rule of thumb, one pound of DME in water will give you a specific gravity of 1.044, and one pound of LME will give you a specific gravity of between 1.033 and 1.037 depending on the type of LME syrup.
(2) You can use DME as priming sugar, as well as most other sugars including table sugar (sucrose) and corn sugar (dextrose), but be sure to use an online priming sugar calculator to determine how much to use based on the type of sugar you use.