I may not have the answer to your question, but maybe you want to check the CRC Handbook of Chemistry and Physics. Its older editions are available free of charge on the internet. Just look for "Physical Constants of Inorganic Compounds", this will lead you to the corresponding chapter of this book. There you should find a large list with all kinds of inorganic compounds, including various zinc salts. Solubility (in organic solvents) is listed in the last column.