I have a RW-4 and RW-8 on my 40 breeder. I keep them throttled back so I think you would be good although a little on the higher power side of things. A pair of RW-8's would be better because you can always dial them down if it is too much. They tend to lose a lot of oomph has they get dirty. Mine are controlled by my reef angel controller with a minimum power set to 40%. The RW series tends to not wake up or be as controllable at 35% thus setting it to minimum of 40. Anyway just make sure to clean them monthly or you will see a pretty large fall off.
They work, and are pretty reliable. I've had mine for a couple years now. Only thing is to really clean them monthly. If you can manage that then they are a pretty good return on investment.