Is this out(85 good for a rune master mage ? I got the whole set out of luck.
If you’re at least level 4 in CoF then it drops the whole set when you get a Set item. As for the answer to your question, I’ll leave that for the masters, but normally the Sets are not really that good as is. They are better used by breaking them down in the Great Bridge Woven Echo and then using those shards on regular gear. But that’s just the norm and I couldn’t say that a whole Set in and of itself isn’t good without knowing the build even if I were one of the “experts” in builds.
You might want to link your build so it can be better answered in relation to your build.
Isadora’s is built around necrotic skills, so no, not really.