+4 ws is 10 rse i think. +5 is 15-20 or more, idk. @akam6666 lol i dissed tons of those, one +7 also.
If you have deco + epi + mastery you have very low chance to fail +6 ( but still can fail). Best effect if you refine a lot. On the other hand crafting something from Red Stones ....is a disappointment (30 crafts - 30 fails).