At first, I used to have a similar problem with the needle going in one side and out the other when Jade was at her skinniest and wasn't eating the prescribed food. Once I got her to get eating again with other foods, and got some meat on her bones, it became ALOT easier.
As gruesome as it sounds, if the needle is out through the other side, sometimes you can back it up slightly just enough so that you are where you are supposed to be rather than having to re-stick him.
As was mentioned in an earlier post, it's good to change the needle each time to make it easier and because bacteria can grow in the needle that is left on from the previous treatment.
Medusa mentioned canned K/D and while Jade didn't like the canned version, she really liked the K/D kibble. I don't know if you've bought some yet but the kibbles are really small and greasy and my other cats kept trying to get some for themselves. Of all the reduced protein diets, that is the only one she ever ate.
I remember you mentioning in a few of your previous posts on the other thread that Braveheart loves his kibbles. I was thinking that maybe he might like something in between wetfood and dry kibbles like Tender Vittles? That way it would be soft on his mouth but still in kibble form. I know it's not ideal food but if he liked it, it might help get him 'filled' out a little more and hopefully a bit easier for you to work with the needle.