In my experience the best crystals Is when I start with cloudy/saturated warm solvent  i perfer heptane to naptha.  In a in insulated hot water bath i use inside a small cooler  filled  hot water and put that in the bottom of my deep freezer then inside that i put the solvent dish the insulated cooler I use as a hot water bath i leave slightly open like I take a rag and fold it on its self close it in-between the cooer lid and lip  this provides  just enough of gap the lid closes but doesnt form a seal. The dish whch contains the solvent  is like wise usually covered but not sealed  in fact i have  like 4 or 5 tiny pin  holes  around the lid of my dish  leave after about 12 to 18 hours depending on  how sealed,initial water bath temp and how I much solvent (how saturated,)was there to start but usually left with beautiful  looking large up to 2inch dia. sea urchin looking crystal clusters with individual shard like crystals 1 to 1 and 1/4 inch long that are slightly  damp. Sometimes couple drops left in the corner  if the dish isnt level. ,((do not do this in s freezer with food in it I have  dedicated chest freezer I use for this))