None. I just used the guide on iFixit but cloned the original drive with CloneZilla to make restoration easier. I did also buy a replacement EM shielding foil so I could leave the original one on the original drive.
Why would there be any modifications required? Buy a 2230 single sided SSD and slam it in. 2230 is the physical size. 22mm by 30mm. Same applies to the retched 2242, and the usual 2280
I have seen quite a few posts of users physically cutting the bigger variants into the smaller one because in some cases it was just an extra blank PCB beyond that small size.
I think the reason was that it was cheaper than just buying a 2230 SSD.