As you have noticed the pin spacing is not standard or consistent.
What I do is to mill a PCB to solder it on to, I suspect you haven't got this option.
You can try the dead bug method. Glue it down on it's back and solder wires to it.
I've been making a part for it in eagle and I think I have all of the spacing of the pads worked out. I reguested a sample from 3M and I will probably print the part out on paper and see if everything lines up before placing it on a board.
I have soldered the microSD connectors in a manner similar to SMD components. Start with a liberal flux application to both the board pads and the connector pads. Wet one corner pad with solder and then position the connector to the board making sure all the internal pins are aligned to their pads. Solder an opposite corner pad to secure the connector, and verify if all the internal pads are still aligned. I then used a 2.5m wide x 0.8mm thick chisel tip inserted through the 'mouth' of the connector laying parallel to the board. Solder is applied to each pad through the access windows on the top of the connector. Dont worry about an excess of solder at this point - just make sure you get each and every pad soldered. Then go back and with a pulling motion drag any excess solder out the front using the soldering iron. Verify there are no bridges and then solder the other corner pads. It takes a few to get the hang, but not impossible.
Duckie