I brewed "these" today. I started by mashing 14# of pils malt and collecting the first runnings for a 5-gallon batch of Belgian Strong Golden Ale. What I was going for was about 1.060 before the boil as I intend to add sugar after the fermentation starts. This worked out pretty well. After the boil the gravity was 1.070 as planned. I will add 1.5 pounds of sugar later.
While that was boiling I added 3 more pounds of pils malt to the "spent" mash plus 2# dark Munich and 1# caramunich 57L. This mashed for an hour, but my math and/or predictions weren't too precise, so I had to add some malt extract to the kettle on the second boil to get an appropriate gravity for a Double before the sugar addition. I intend to add 2# of D-180 after the fermentation starts.
Long story short I think I made a triple double.