NOT saying that cut to tip heads are " BAD" , just saying that at higher arrow speeds, a broadhead with less surface area (most NON cut to tip heads....shorter blades) will GENERALLY penetrate as well or BETTER than a cut to tip head.
Velocity is the key. The faster the arrow, the better for replacable blade heads. Slower arrows work better with cut to tip heads.
50 lbs is more than enough to kill deer...CLEANLY. just make sure you make a good hit. PLACEMENT is MUCH more important than KE or broadhead type.