Originally Posted by YooperBrew
You just adjust the grain upward (keeping the % the same of each grain) until you get the desired OG.
Could that result in some undesired concentrations of flavors from the specialty grains? Depending on what's causing the inefficiency, if it's a lack of protein activity wouldn't you still be getting the full taste of say, a chocolate malt, even if there is less starch conversion? I'd be more apt to adjust only the base malts.
Edit: I didn't see his recipe before I posted. I don't think there would be any harm in upping all three grains. That's a lot of wheat malt as a percentage, I'm guessing the efficiency is going to suffer a bit just from the recipe.