easier to solder to the controller contacts if you have the room all you do is solder one contact to the button then the contact diagonal from it on the tact switch to ground ... do it for all the buttons !
im prepared to get a lot of SH!T for this but heres bacterias video for mounting buttons in the case i dont think its a bad video at all and i did it in my portable worked great except for the dpad ...
this will work for all buttons and worked fine for me