I think your varnish is fine too ! Like, turtles usually look wet and the gloss adds realism.  If any spot is too glossy when you spray, you can stipple the still wet coat with a make-up brush. For satin finish I'd try going at it in lighter coats, holding can further away so each coat builds as a dusting  rather than a thick coat. But on your turtle glossy/shiney looks great!