I prefer filling AE shocks over the losis. Easiest way is to remove all old fluid and clean shock body. Put new fluid in and move the shaft up and down slowly to get air bubbles out. Now push the shock shaft up until the piston is around 1/4 of an inch from the top of the shock body. I actually use my front wheel nutdriver, pinch the driver between the shock body and the shock end. Then drip a little more fluid in so it is just convex over the top. Screw the top on and should be good to go.
When bled properly, the shocks should extend back out roughly 1/4 inch or so by themselves (rebound) when you push them in.
You want all four shocks to be pretty much the same. With the method above, you should get pretty good at doing them right on the first time. The nutdriver trick ensures they are all the same, you just have to be good at getting the fluid to the same bubble above the shock body.
When you push the shock in, there should be no resistance as you get to the top. If there is, you need to unscrew the top a little at a time, push the shock in till some oil comes out, then hold it there and screw the top back tight.