Does your wife still have them and what is her current size?
Yes, she does. Send mer a message and ask, she may have it written down. Somewhere between 5 and 6k cc.
Now I kinda found your opinion on this type quite interesting as. For exp the likes of Foxy Menagerie that have reach today no less then 10.000cc's bust size utilizing those type of expanders.( without any complications ) Her suregon was no other then Dr Plovier in Belgium. That as become today very well known for his skills when it comes to XL augmentation.
So interesting I find, why his chose was what you say should be avoided at all cost.
You should probably ask him, then.
No with all that said, it seems within the USA those surgeons that are willing to work with expanders from a purely cosmetic standpoint. Opt to place them partially under the muscle ( which I personally prefer from if only a visual point few then fully over. ) But in the case of Foxy. Dr Plovier chose to place them on top. Which I assume might have it's advantages when it comes to the expansion especially when going XXL as you not also stretching the breast muschle but only the breast pocket itself and the skin.
But I would beleive one of the big disadvantages of fully over when going XXL. Might be the lack of the support the muscle might be able to offer when it comes to support the weight if the implants. And although Foxy is a extreme case. It is clearly showing how the skin alone is not able to offer the support needed for such a huge bust. But I also doubt Dr Plovier ever excpeted that she would take her expander literally their absoulte max possible capability.
The muscle is not directly supporting, it is actually more likely to push it down. Drs that do overs, IMO, are less concerned with aesthetics. Both wives were under the muscle for all surgeries, but realistically massive CC numbers means they migrate out. Implants above the muscle look terrible, IMO, and sag quickly. I believe this is due to the placement position's depth, not due to the over/under posture. More at the depth of tissue above the implant softening the shape above, and providing support below.