If I remember right, I used a nerf bullet with the plastic cone chopped off for securing my SSD in one of the HDD trays in my G750. Honestly as long as you get something to hold the SSD secure against the sata port, thats all you need. Just something to fill the gap and allow the lid to screw back on. Normally the laptop should never really be jarred or thrown around where it could be a problem. Even a piece of cut Styrofoam should do the trick just fine. This was never an issue for the way I had mine hooked up and it was that way for a couple years before I sold it.
(ROG has simply become too expensive compared to the competition with same specs... 😞 )
MSI GE75 Raider 10SGS - i7 10750H - RTX 2080 Super - 32GB Ram - 1TB WD NVMe - 2TB 960 EVO - 300Hz 17inch Display
RETIRED: ALIENWARE R17 R5 - i7 8750H - GTX 1070 @ 1.9Ghz - 16GB DDR4 - NVMe 970 EVO 1TB - SSD 960 EVO 1TB
SOLD: ASUS G703VI-XH74K, RETIRED: ASUS G752VY-DH72, RETIRED: ASUS G750JH DB71 , RETIRED:ASUS G74Sx DH72