Silken Saturday 
Latin quarters?   CASA
NASDAQ setting   NYNY [not the usual NYSE, which I thought it was]
Deal prerequisite, maybe   ANTE
And a wide range of interesting entries:  
DELSHANNON, CIRCE, CAPNCRUNCH, LADYBEARS among them. 
 Surfer’s perch   CREST [unusual reference to surfboarders; I now first think computer user] 
 Improvisatory composition   TOCCATA [It could be, I guess, but it’s a keyboard piece designed to show one’s “touch,” from the Italian tocca {sic}] 
 Carpenter’s gadget   NAILER [they’re big, heavy, and powerful --- hardly a gadget]
RATING:   
 
 Three grins = Loved it; Two grins = Enjoyed it; One grin = A bit bland for my taste; One teardrop = Not much fun