Depends what you're doing with your truck. I don't tow but occasionally haul firewood through hilly areas and I use a 11"x7" plate and fin mounted in front of radiator and ac condensor. I do not have the original radiator cooler bypassed and my temps stay at about 170f, 180 is the highest ive seen it.
If you tow heavy loads or sit in heavy traffic in the arizona desert, an electric fan would definitely help.
If you live in cold winter climates, dont bypass the oem radiator cooler section unless its leaking. Add your aux cooler from the return line. Reason being, the radiator cooler actually helps get the fluid up to temp faster when cold. This way the fluid passes the radiator and gets warmed initially, but then passes the aux cooler to spill off any excess heat.