See if you can find some different style wheels to try before buying anything.

There are lots of variations out there and lots of wheels in sheds everywhere.

We have always commented on Ag Talk about how nice it would be to have a pool of closing wheels available for people to try in many different areas.  This might be something state extension or soil and water districts could get involved with.

Until you try different combo's under your exact conditions and soil types don't listen to anyone's advice on what is best including me.

Here are a few threads with pics about my own attempts. I tried the one 15" spader and one 13" rubber wheel and was disappointed. This combo received rave reviews on here but in my heavier soils ranging from sticky black wax to hard red clay it just poked holes in the ground leaving an unclosed trench in too many areas. 

I ended up with the Dawn curvetines with 1/2 rate springs which do a much better and uniform job across all my conditions from worked to no till.

http://talk.newagtalk.com/forums/thread-view.asp?tid=634090

http://talk.newagtalk.com/forums/thread-view.asp?tid=596409

http://talk.newagtalk.com/forums/thread-view.asp?tid=542135

http://talk.newagtalk.com/forums/thread-view.asp?tid=270053

http://talk.newagtalk.com/forums/thread-view.asp?tid=208955