Your original watercolor "At the Lounge" is a quintessentially typical subject matter for Tarkay, a pair of elegant young ladies in low neckline evening wear seated at a table, their heads joined by a framed picture on the wall behind them, a pleasing trick deliberately intended to unite the composition, and the purple dress and the legs of the table sinuously emerging towards the viewer as if to draw him in.
As for value, I have to preface what I say by reminding you something you probably already know (so forgive me for saying this if you do) a painting in watercolor is always worth a a lot less than one in oil or acrylic, as watercolors are considered more perishable than a work on canvas and, besides, are usually less finished than an oil painting.
Looking at recent comparables in the auction sales records, at the top end, this equivalent sized watercolor sold for $1500 and at the lower end, this one (also the same size as yours) sold for $750.
So I would give yours an auction value in the range of $800 - $1500.
I would therefore insure for at least $3000 as this is the full retail gallery or replacement value.
I do hope this helps!
Itzchak Tarkay (1935 - 2012)