Depending on the nature of your protein and the quality, taking a it directly with a fairly acidic juice could be hurting you, more than helping. If the Whey is of low quality the acidity of orange juice can denature the protein. It is probably not a huge deal, but i have always stuck with apple or white grape for a carb source(as far as juice is concerned).
Also, instead of buying dextrose or just putting table sugar into your whey, i have found that mixing lemon-lime gatorade mix with chocolate whey tastes pretty darn good.
I am an endo so i never use many HI Glycemic carbs, the only time i use it is at the end of a hard workout where i have gone to failure. Even then i only use about half of my Carb allowance for that meal with the gatorade mix, and the other half comes from blended oats in my shake.