tubing is much easier to work with than rigid pipe, but you knew that. Making turns especially 45degree turns with rigid pvc
increases the pressure and reduces flow significantly.
I keep my sump in the basement with around 22ft of head. Running a Reeflo Barracuda I'm still not happy with the amount of flow I get at the tank. One of these days, I will swap out the pump for something larger. I would suggest that you should figure out whatever pump the specs say you can use, and then go one or two sizes up. The worst thing that could happen is you put a ball valve at the output and throttle it back a little.