Trust me, you want male plants. The Jersey series from Rutgers is far superior to the older cultivars.
2 year crowns allow you to harvest a year earlier, provided they have been fed properly.
To some extent, the spacing at which you bury the crown detirmines the stem thickness. 6 inch spacing gets you thinner stems than 12 inch spacing.
There is no tenderness difference in thickness, just longer or shorter cooking time. If you can or freeze, you may want to sort spears according to girth so they cook evenly.
This site has the best prices and directions:
http://www.jerseyasparagus.com/
Online they quote large amounts, but they will sell smaller amounts if you call them on the phone.
I'm not a business partner, just a market gardener who has done a lot of looking and I've been more than satisfied with their products.
Harvest diligently at 8 inches. Only 8 inches from the tip to the base will be quality eating no matter how tall it grows. Better to cut it at 8 inches and let it grow a new spear opposed to wasting energy in tall tough spears that go to the compost heap.
Asparagus emerges about a week after Daffodils bloom. Harvest for a week the second year and 6 weeks for subsequent years. Be sure of where you want to plant because established asparagus doesn't like to be transplanted and it lives from 15-30 years.
Good luck.