Hello Gary Goldsmith and MMD -- in the light of your recent posting,
I shall answer publicly.  ;-)

The Ariston originally might have had only seals on the top edges and
on the center drive; however, the complete coverage with thin cardboard
on top of the pressure chamber is the "agreed upon" solution between
Ariston restorers.

The benefit of reduction of leakage of air far outweighs the benefit
of originality (especially, as you won't see the difference unless you
remove the top).  For equal height distribution under the top lid,
strips of the same cardboard will do on top of the rest of the edges.

I had the luck to learn under tutelage of one of the top Ariston
restorers in Germany.  While I'm not saying that you will fail, there
will be a long way ahead of you for sure.

If you have questions you can send them to me ... and if you get too
fed up with the darn thing, then you can send the Ariston to me.  ;-)

Musically,

Ingmar Krause
Coquitlam, British Columbia, Canada
http://www.grindorgans.com/ 
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