Excellent question, Sharpco.
I have wondered the same thing ever since I first put my DWF-200 and DWC-200 on my T4. Except for the dry only constraint, they worked like a charm. I asked Tormek the same question, and was told that the wheels would disintegrate. To be fair, Tormek has only marketed these two wheels only for dry use and only for the T2. This seems a missed opportunity to me. The T4 was a major influence on the design of both the T2 and the T8. Knowing that both wheels were an exact fit for both the T2 and the T4, I wonder why these wheels do not work wet. Unlike the later, larger diamond wheels which are designed to be used wet with ACC, these two wheels are designed to be used dry. Perhaps the two designs are not compatible.
I hope that someday Tormek will introduce a series of 200 mm diamond wheels which can be used wet with the T4. I realize that Tormek emphasizes the flagship T8, however, the T4 is also a trooper.
Ken