I had about the same results with paint thinner and a small square of paper towel. The ridges and high spots tend to burn through the unwanted tampo and the underlying paint too easily, while the flat panels need a scrubbing.
I have used denatured alcohol and a cotton swab to remove the graphics from an AW Firebird. Just dip the swab into the alcohol and carefully rub on the graphic only. Take your time. The results were great. I have not tried to remove the graphics from the Bowtie series.