vanderzac,
In your case (as same as in my case) you have to make sure your ground loop is as huge as possible. Also you can add desuperheater for domestic hot water and enjoy free hot water. This will add extra capacity to your system.
If you are dead serious about building a rig I can only suggest to you to build it right and strong.
Don't go with toys they don't drill (actually they drill your brain
). Make sure you buy a GOOD drill bit. My bit is as sharp as new no even a sign of wear or chip after about 1000 feet of drilling. Yes it was mostly clay and very compacted sand but I had few very nasty rocks.
Go over my pictures and component's specs. I spend a lot of time experimenting you can just copy/paste and save a ton of time.
If you have any questions I will gladly try to give you an answer.