Seat, repair or not?

[Don R]

 My 5511 sandcast is mostly original, it had incorrect handlebars and exhaust. I re-installed the original rear rolled rim ( I had to buy another of the po's bikes to get it) I sold a bike to buy a replacement exhaust system, and painted a set of Honda sidecovers so it looks pretty good. I'm trying to not restore anything that's original and usable.
 Anyway the question is the seat foam is dry and getting flat, what's best for the bike?  Add some new foam to the top of the padding, buy a repro seat for riding and set the slightly flat original on a shelf or buy the Yamiya red seat foam and install it under the original cover? The cover is in good condition and the Avon Skin so soft seems to have given it a new life.
 I'm leaning toward the Yamiya foam, that seems to be the best balance between originality and functionality.

[patriotcommercial]

I reused my original cover with new Yamiya foam.  I got the foam and put the cover over the foam.  I used spring clips to hold the cover to the base for a week or so and kept pulling the cover tighter, eventually it took the shape pretty well.  I did have to sculpture a piece of foam on top to take up some slack in the cover.  Also I had a trim shop sew a piece of black vinyl strip around the inside of the lower piece that gets fastened to the base.  Mine had stretched out holes at the attachment points.  Now that it is together you can't obviously see the sewn in piece, unless I point it out. Came out very nice

[Don R]

 Thanks, I did a cover on a 76 750F super sport like that, it went well. I have a 400F to practice on too,  I'll go that way.

[Don R]

 I got the seat foam from a Yamiya dealer along with an order for fork gaiters and a DID cb400F wheel/spoke set. The price wasn't as bad as it looked a couple years ago and he took care of the shipping since I lumped it all together.
  I'm nervous about the bent over trim pins and speed washers coming off intact. Thanks for the tips on installing it.