It depends on your desired temps, and cage volume.
All the animals I have in large APs (4x2x2) get cooled in the winter, so I have no need for RHPs. There is no way that flexwatt would get a 4x2x2 up to "summer temps" with my cooler room temps in winter.
I have no experience with RHPs, but I'd bet that you'd be able to fully supply all needed heating with them. They provide a large basking spot and are known for raising ambient temps nicely. Talk to whoever you purchase a cage from for wattage suggestions.