Swashdrive have recommet i think because you can over power your machine with a critical. I have 2 machines thats going down and i have replace the motor -after the third machine i have go and measure the volts - and i have seen it !
Critical have more volt as showing in the display. from 5 to 8v its most 1v more -after 9v - 12v its was 2v more - with 14v i have measure 18V ! so when you run the machine with maybe 11v -you let it really run with 13 to 14v and thats can burn the motor with the time. But thats the issue with every rotary. So i have change my Powersupply with a spinner and venom2 and now its all good. With the clip you adjust the hardness of the needle force - with the weight you get more stroke and a extra punch -its more like a coil. When you use a rubber on the end of the clip -the clip is working tougher - with the rubber on the top of the clip you get the needle faster in the skin and with less time out. You need some feel and time to find your spot -and use a neon light to find your speed