I think any of the varieties will do good for you. Plant it as early as you can get on your ground. It is a cool weather crop, and as others have said it will go to seed when it gets hot. I always have spinach go to seed, and in the spring when the snow leaves, there is spinach already growing from last years seed. It gets going early and is my first harvest.
Gardening at 5000 feet elevation, zone 4/5 Northern Utah, Frost free from May 25 to September 8 +/-