There are numerous things to mind carefully. The pump needs to sit at least 15 degrees off horizontal. If your vertical lift is really 100 feet, not 50, your flow with the first system listed goes to 5 gallons per minute.
Also, your local codes may require a certain GPM supply to the house and you may have to start with that as a baseline.
Also, I can tell you all this stuff, but it's your house and it's hard to cover everything, but here's a couple of ways, the most basic being this:
Use a 1/2 hp. nominal 10 gpm 240 vac submersible pump. This will give you about 10 gallons per minute at that lift (50 feet static lift + pressure tank pressure assuming 30 psi. cut in and 50 psi. cut out + flow losses in piping). Run sch. 40 PVC (1 1/4 inch nominal size) below frost depth to keep flow losses low and you can run #10 copper wire (10/3 w/ gd. for 3 wire motor or 10/2 w/ gd. for 2 wire motor) to the pump. At this wire size you can run up to 1000 feet without making the motor unhappy. Get a 1000 foot reel of the wire if you can, buried splices suck. If you have to splice it, sleeve it in conduit to a weatherproof junction box mounted on post high enough to keep it out of the snow and make your splices there. Makes sense?
Now here's a better way, more complicated but better.
If you aren't already saying, "whoa, what the hell?", check this out.
Use a 1/2 hp pump in your spring box, nominal gpm 16-18. Push it through the same
1 1/4 inch PVC to a cistern close to the house, say 600 gallons or more direct burial polyethylene. Control the spring box pump with a float switch and feed the house with a Grundfos MQ-4-45 booster pump in the basement or crawl space or wherever your treatment stuff is. Now you've got the same wire run to the spring box pump and can pressurize at the house with power there. You get 16 gpm into your cistern and 16 gpm at 30 psi at your house plus a cistern to dip out of when the power fails. Or go 1/3 hp 10-12 gpm at the spring box, go to #12 wire and let the cistern take up the surge capacity when you house is using more than your spring box pump is putting out.
If your skills as plumber and electrician aren't up to the task, sigh, know your limits and see about a really good iron filter if that is the only problem. I use some that can treat up to about 8 ppm.
Free advice for what it's worth, and one more disclaimer, what you do is up to you, but don't try it if none of this makes sense, okay?
Good luck.