Well, the kickstand stays quite good, i doubt it would accidentally open.
I need to fast remove the card, so the magnet does the job really good, when i remove the magnet the card is almost instantly gone.
I insert/remove the card very often, becase i need to copy or edit files for raspberry pi, and windows doesen't recognize linux partitions.
About the sim card slot, it is verry easy to do, but i simply cannot find any space left for a second sim slot, but the idea is simple: you need to solder to the sim slot pins, some thin wires, cross them above the battery, and solder them to a second sim slot above the battery. When you want to change sim simply put the phone on offline mode, change the card , put the phone back on normal mode (this works in theory, but i did not tested). This has been discussed on this thread before, i said i would do it, but unfortunately i have no time (and space left in the phone).