After trying these suggestions with a thinner SSD and couldn't get anywhere I used a bent paper clip, L-shaped, to act as a hook. One end I was able to simply hook under the drive and pull it up to install that ends screw loosely. The opposite end I inserted the paper clip through the antenna grate, again pulled up on the drive, installed the screw and carefully pulled the paper clip out.
I found that slightly lifting the board allowed me to get the connector in a better position to rest on its female counterpart. Then with a smudger just push it into place.
I'm about to order a late 2015 27" with 512gb "Flash".
• Since there will be no HDD installed by Apple will there still be everything I need to install my own?
• If this is the case is there any reason why this drive couldn't be an SSD?
• 2.5" or 3.5"?