Given that the Saaz plugs are usually 1/2 oz each and that they are absolute mothers to cut through, I think you might have a tough time dividing the 1oz Saaz into a 3/4 oz and 1/4 oz additions. You may have to go for 1/2 additions for each.
For dubbel though, I would probably skip the aroma addition and just do 1/2 Saaz at 10 or 15 minutes.
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