You're right aeajr, 64oz is 4 not 5 lbs. I don't know where my math was when I posted that.
Common reports on models with 100 watts per lb suggests that the climb would be well over 45 degrees and closer to vertical. Some time back some brave soul here actually listened to me
and put in a 75 watts per lb power system and reported that the model went uphill at about a 40 to 45 degree climb at a pretty fair clip and well above any sort of slow or near stall manner. So I tend to go along with the reports that 100 watts per lb is going to be more like a good clip at around 70 or maybe even more degrees.
I got a taste of this myself when I put together a flat foamie 3D model about 4 years back. With 120 watts per lb it not only prop hangs on about 2/3 throttle but it goes up vertically until I tell it to turn around on full throttle.