This is what I have on an early 7200 standard planter. Stamped steel closing wheel brackets with adjustable handle and multiple position slots and eccentric mounting bushings.

You can get new replacement closing wheel brackets at RE Skillings at New Carlisle as well as different types of closing wheel setups.

I tried the one rubber one spiked closing wheel setup that was supposed to work everywhere. Could not get it to work satisfactorily in my conditions. 

There was also a spacer used on the hub when there was a 15" spader used on one side and a rubber tire on the other.

In very dry conditions it was okay but all too often I saw this. Punched holes on one side.

I ended up going back to 2 rubber tires and then tried 1 row of the Dawn curvetines with the 1/2 rate spring and saw much better slot closing. 

This was the results I was looking for. 

In short don't listen to anyone including me on what will work best for you in your situation. You need to really compare several types and styles side by side to see what will work best for you in your soils and conditions.

We have often talked about how nice it would be to have an exchange of different closing attachments that people could try out before buying. The only issue would be getting them shipped to all the people that would like to try them. 

Good luck in finding something that will work for you