Pixel and I spoke to a different engraver today at length and this one signalled that there is a lot more flexibility in depths than we previously thought.
Because of this Pixel is going to take the weekend and see how he can tweak it using this new ability. The token should be nicer because of it, so it will be well worth the slight delay.
The order is in and the mint now has the money, so there is no going back! We hope to send in the final artwork in on Monday or Tuesday, and to have another quick call with the engraver early in the week to be sure everything is in order before he goes to work cutting the dies.