I've been running a .91 Magnum pretty hard for six or seven years now. It was in an Astro Hog until 2 years ago when it went into a U Can do 3D.
I have been running a pump since I changed it to inverted to go in the U Can Do. It really has been good to me. I've been using Omega 15% in my 2 and 4 strokes for 20 years. I use 15% for the a reliable idle and Omega for the castor content in the 4S. Since it's in the flight box I use it in my few 2S as well.

Ken