Quoted from Chisox:
I use 1/2 hp cast iron Zoeller pumps. The water backup has been triggered and can keep up during storms during power loss or when there’s a problem with the main pump. I thought about having a second pit dug and/or adding a second electric pump. I also have flood insurance and coverage for the toys in the basement. All downspouts are connected to pvc underground that takes the rain water at least 30 ft away from the house. We’ve had 3 inches of rain already and it’s going to pour for two more days…good times!
I have both pumps in a single pit (pit isn't anything special other than being deeper). Not trying to twist your arm about a 2nd pump, just that it might be easier than you think. Especially if you have some very basic plumbing skills. If you don't have room, I'd just buy another pump and stick it on a shelf as backup insurance.
Your flood ins.: Is that the FEMA policy (i.e. a real flood) or just thru you typical residential policy (i.e. State arm, Allstate, etc.)? My State Farm policy covers sump pump failure, but I also bought a preferred rate FEMA policy since the area I live at is newly developed and I just was a little worried just in case the developer screwed up something or we got one of the 'once in a 100 years' rains. That wasn't covered by State farm.
Sorry, don't mean to sound like I'm nagging. I finished the basement a number of years ago and go out of my way to keep it dry! Pins, bar, theater, etc., so a bit of an investment down there.