I have several machines also - I put a color dot on the machines - RED / Green / yellow - that matched pin heads that I had - made a chart on fabric with batting behind it: across the top is the size of the needle (ie 60 - 70 - 80 - 90) and down the side is the type - universal, quilting, topstitch, metallic etc. Then I put the color coded pin in the slot to match the needle in the machine
when I take it out (say metallic) I put it where the pin is on the chart so I can use it again. Hope this helps