[Diabolical Artificer]

I'd agree with adding a few turns/taps on the primary & secondary, you might never use them but they're handy just in case your calculations are a tad off and you get more voltage drop than intended on the secondary. I do this on most of my tfmr winds, that is if you have the room. Often your winding ends half way across a layer anyway and it's no bother to add a couple of taps etc.

Andy.