Quite right, although it may appear the same, it works completely different, a different angle approach.
The Tana and Daiza provide different functions, we stack them, a Daiza can sit on top of a Tana and improves its performance. In fact the Daiza was developed for that specific application. However we quickly discovered it had its merits when used without the Tana.
Depending on setup, it can be so effective it does not need "isolation" anymore. That is something you'll just have to try.
If you get Custom sizes which are between the 345 x 325mm and the next size up the 483 x 400mm what price might they be ?