Being slightly lower in front may help aero slightly but remember it also effects the rear alignment (if drilled for canted axles). The amount of bend of the dfw axle plays a role in the drill heights. As long as not an excessive amount of bend it isn't that hard to get it really close to right. Keep in mind that for every degree of incline or decline (fdw bend in our world) a line will change from level 0.017" for every inch traveled.
Sorry I didn't tell you exactly what to do. But there are many ways to skin the cat. With the info given you should be able to figure it out no matter how much bend u use.