Here's a side profile shot compared to my phong 6538 (on top):
Obviously the "swoop" or tear-drop lug tip of the phong is preferred but there is enough material there to carve out the swoops to be much more accurate. The rehaut of the tonney case is very similar to the phong which is what leads me to believe that the same source provides phong, MQ and now tonney with the same raw mid case blank. Then each seller finishes off the details (like the lug tip swoops) which is why they vary from sample to sample. All other dimensions seem to be the same as phong.
Yes, an ETA wil fit any of these cases with the right adapter.
Given that the bezel is brass alloy-based, the complete tonney case set for $600 is a great value imo. Phong and MQ charge $300 for a bezel alone. A complete big crown phong case will run you anywhere from $1200-1500 depending on how he feels that day. Upon second look today, I actually think the bezel is better than phongs. (Note that the bezel on my 6538 is a gen service bezel and has a different profile to an original 6538 bezel.)
Case back stamp on the tonney case is incorrect "1958" but it's a common tell from other Vietnam cases I've seen floating around the market.
I could carve out the lug swoops but this was a impulse project and I just wanted a beater to save wear/tear on my other builds. I will likely part it out at some point, but the genesis of this was R&D. Someone had to take one for the team