I think it might be easier for you to try a pre-killed mouse for a few times, and then try going to frozen thawed. After all, pre-killed will definatelly be the right temp

I feed frozen thawed myself, but it's taken me a feeding or two to get the temperature right.

I understand that ocasionally you get a ball that won't take anything but live, but it's a lot safer for the snake if you can get them onto dead prey