Gary makes a very good point. If you have more than you need you can dial it back a bit or tee it off to run other devices or let it go to waste.
Further, evaluate the performance curve for whatever pump you choose vs. the head (vertical and friction head combined, note: friction head can be reduced by using larger pipe ). This will tell you how much gph you'll actually get at the tank. Then take a look at the electricity consumption to discern which pump may most efficiently work for your set up. For example in my case the Iwaki which genrates 2000gph will on my system outperform the sequence which is rated at about 5000gph simply because it is higher pressure and has greater head capacity. Once you've figured all that out get reviews from folks who have used the pump you wan't for a priod of time .