I recently acquired use of an old Omega C760 dicroic head. To see if diffusion printing suits me, I snatched the lamphouse and condensers off of my Beseler 23C.
Basically, I have the Omega head sitting, loose, right on top of the negative carrier. However, since the light exits the head at the right side, it had a tendancy to fall off and crash to the floor. I felt that this was less than optimum.
So, I put the light head back on, and set a large plastic bottle of Aunt Jemima syrup on top. It held well, but under the yellow safelight, Aunt Jemima looked like LaToya Jackson after a weekend in Vegas. Unacceptable.
For the moment, I've settled on a large can of baked beans. Bush's brand, at this point, seems to be the best.
32 oz. canned tomato sauce also appears to have possiblitlites. As my testing continues, I'll report my results.