Any photos?
When I face a delicate porcelain I will try and dry cut using a Sigma cutter.
I always find I get the cleanest cut that way.
If it's more than one cut, then I'll score with the wheel anyway and then carefully use my grinder (with Marcrist ck850 accumax blade) about 0.5mm from the score line. That normally will result in a chip-free cut which if needed, I'll smooth up with a Silicon-carbide disc on my grinder afterwards.