All drag that a wing produces is already included in the power you need to do a horizontal flight with same constant airspeed! (With climb angles less than 30° we can neglect that influence on the induced drag, what Hitech already mentioned (sin 30° is still 0,86))
That means if you do a horizontal flight at a constant speed, all further power will directly increase your climbrate, and you donīt have to care about drag. The problem is to know how much power you need for the horizontal flight.
Of course reality is not so easy. In a full power climb you need other ailleron deflections compared to a horizontal flight at 160mph. Maybe your cooling flaps will open widly (full power at low airspeed). This can cause different drag conditions.
The steeper you climb, the less important becomes a wing, or lift generally. In a vertical tailstand you donīt need any lift at all (like a rocket), because the lift vector is pointing now vertical to the gravity vector. Lift simply canīt help you anymore to overcome gravity. The steeper the climb becomes, the better perform planes with high wingloding (read: small wing, small surface area, ...)
btw, the thrust of a jumo engine is not constant over the speed range. At 330mph it drops to 1650lb near sealevel, compared to 1980lb for 0mph.
niklas
