Barry is correct in saying 0.001” to 0.002” over groove diameter.
Remember that most of the coatings will add a thou or two to EVERY dimension. Some guys get caught with bore riding designs forgetting that now the nose section will be larger, can make chambering difficult in some rifle/cartridge combinations.
Some guys I deal with report better accuracy with lubing and sizing a coated projectile as well. Seems like a lot more work to me, but it’s all about experimentation.

DC.