When duplicating a TOY43 profile it is highly recommended you use the dedicated jaws on your machine (eg: side 'B' on a Silca Bravo Professional jaw).
The important thing is to hold the key from the profile, NOT from the base of the blade as you'd do with most residential and other automotive keys.
This way you're holding the key from the centre-line, and any variation in the height of the blank is irrelevant as it will be cut away by the cutting process.
When cutting a TOY43R you may want to use a different side of the jaw for good results.