One of the tips in the Tormek manual bears highlighting.

If you are running off a projection figure using the Turning Tool Setter and doing a deal of shaping of the pointy end with the BGM and bench grinder, it's worth resetting the projection half way through. Cos losing metal obviously changes it as you work.

The Tormek manual is well worth a read even if you have another brand of machine. The US website has a dig copy but you have to be a registered user. GJ however has found an earlier edition on an Oz site along with vids on how to use each jig: TORMEK