"Kitchenware" Ø 6" bubbler

[Garouda]

So far I got good results with my Ø 3" VM column.
In fact I got the opportunity to buy some asparagus pots on a German EBay auction website. Cooking asparagus is quite popular in Germany, but may be some people wanted to get rid of unused wedding presents, so I could get them at a very low price, less than 5 euros each on average...
Those pots are Ø +/-160 mm or +/- 6" for a height of 210-240 mm.
I have eight of them, seven plates plus a dephlegmator (CM).
Hence, the idea of building a Ø 6" bubbler by stacking those pots. That's why I wrote :"kitchenware bubbler..."
For the bubble caps, I'm using SS Ø 115 mm X H 55 mm food containers.
For the sight-glasses, I'm using Ø 5" tri-clamp ferrules and Pyrex glass. The size 5'' is dictated by the size of my food containers I want to be able to remove.
At this stage, I'm drilling holes in the food containers (bubble caps) and I'm concerned about the size of those holes. I assume the surface of all those holes must be >= than the risers surface, am I right?
My intention is to drill bigger holes let's say Ø 6.5 or 7 mm and cut some splits every odd hole...
Here some pictures, I lost the ones where I melted the pots aluminium bottom...

0 to give an idea.png

1 some geometry.png

2 cut the ferrule.png

3 welded ferrule.png

4 sight glass.png

5 food containers.png