Q) I'm having a real problem with blowing people out, left and right... any advice?
A) Blowing people out... Outlines you mean? This can be mediated a few ways, all in combination with each other:
1) Tight stretch, always! Nothing else can go right otherwise.
2) You should have plenty of needle extension- at least 1/8" with the armature bar in the down position.
3) Using a combination of tight stretch and enough needle extension, the points should penetrate automatically to the right depth... The skin resistance should balance the power output of the needle group, so it naturally goes to the right depth and then retracts. The tube tip should not serve as a "depth gauge" and should never touch the skin, in theory.
There is no secret ingredient- it's all about having the right touch. These guidelines should help. When in doubt, lower your power, then add as necessary. Thinner skin (inner arm, etc) is more blowout prone and needs lower power than thicker skin... When outlining a sleeve you will need to continually adjust your power as you move from place to place- there is no one size fits all power setting.
If your power unit has a meter, I recommend that you begin ignoring it and learn to gauge your power output by feeling the armature nipple. The strength of that is a real indicator of how the needle will hit the skin... While the meter is just a number.