Problem being its solubility in water, only 8g dissolves in 100ml water. It comes very hard in bottle and being hygroscopic very difficult to weigh as well.
I would try to procure 80% phenol commercially or use another solvent as Ayad said. Combine 555 ml of aqueous phenol (or 500 grams of phenol crystals plus 55 ml of water) with 70 ml of m-cresol. Change the relative amounts according to needs. Phenol is horrendously corrosive and is tremendously hazardous. Use extreme caution when handling this very toxic substance.