Hello.
I hope this is useful - your title has PGT, and my experience is of PGT-A not PGT-SR, but I thought maybe you meant people to respond about PGT in general (since -SR is less common). If not, please excuse me, stop reading now, and best wishes with your treatment!
I wish I'd been clearer about two sets of things: one, how the test itself worked at this clinic, and two, how the clinic expected to communicate about the test.
With the first one, I wish I'd asked:
How much does this specific clinic and lab do this kind of testing? Do they have lots of experience, or not really? What are their statistics for successful pregnancies following testing, and are those in line with national averages? With PGT-A, I would also have liked to understand how the baby's father's age factored into the aneuploidy rate. My clinic only gave us any indication of how maternal age had an effect, and I later found out that paternal age was (for us) a really important consideration we hadn't been warned about (in fact we'd been brushed off when we asked about it). I know PGT-SR is screening for transloctions (is that right?) but my understanding is that it'll detect aneuploidies too, so I wish I'd known about that. I also would have liked to understand what they expected to see - I remember finding the results hard to understand (this feeds into my second set of questions).
With the second one, I wish I'd asked:
How will you deliver the results? Will you talk to me on my own or can we both be on the call? Will you expect to discuss what the results mean during that call, or will there be an opportunity later? How quickly will I need to make decisions after that initial call?
For me, the big shock was that a few hours after we got results in my first round, we got a series of emails asking us to sign forms to destroy all the embryos from that round - we hadn't had time to ask questions about what the test really meant, or anything like that; we didn't have time to talk to each other, and it felt really hard (this is partly because of timing - we did it just as there were cases in the news about an older version of PGT where people had just found out they'd discarded viable embryos in error, but of course that sort of thing makes you want to stop and take time).
I was aware that there's a risk to thawing and re-freezing embryos, and I was aware that, like any test, PGT can throw up false negatives and false positives, but I know people who were shocked by both of those things and I do think they're worth considering. (I might not have tested a top-grade embryo, another time, but that's just me).
Finally ... I wish I'd talked more to the father (he's not my partner, not that this is medically the point) about how he understood the test. And I wish the clinic had talked more to both of us. I thnk he went away assuming that if we ended up with aneuploid embryos it meant we'd basically proved we wouldn't be able to have a healthy baby, and it's not about that, but I think (forgive me for generalising) that sometimes, men are less likely than women to want to think about the details, and sometimes clinics also cause problems by explaining lots to women and giving men the impression it's all plainer sailing than it is.
Apols for the essay but I hope it is useful! Good luck!