I would look somewhere in the 350-450 GPH. Just make sure that numbers relatively close to that are head pressure adjusted. Look at the graph with whatever pump you are looking at to see where the GPH lands with the head pressure you mentioned.
A 450 GPH pump that can't handle any head pleasure would be worthless.
The cool thing with DC pumps is you can adjust the flow to your specific needs. Dialed down, lower flow and Watts used, and dialed up the more of both.
DC pumps usually have a "sweet spot" where the max flow and minimal wattage are at a good Ballance. DC pumps tend to have minimal flow gain relative to Watts used above that sweet spot.
In my experience, buying the cheapest pump to meet your needs rarely is a wise long term investment. A pump, especially one that is the heart of your filtration, need to be as reliable as possible. Nothing worse than having a return pump fail... It NEVER happens on a weekend when you are looking to go to the LFS anyway.. Usually a Holiday, or Sunday after the stores are closed.