The HDMI adaptors are a bit over-insulated, and won't fit some connectors due to this. Fortunately, they can be shaved and then peeled, using a sharp knife (and a cutting mat, thick gloves, and eye protection). This reveals much-thinner sockets, attached to a PCB, and a plastic collar around the larger socket, which can also be removed. If that's still not enough space-saving for you, the larger shield can be pulled off (I haven't tested how well it works without a shield yet, although it still plugs in fine) and the end of the PCB shortened by about 5mm, saving even more space. Some insulation coating may need to be removed after shortening the PCB.