If Im putting a double in a latte I normally let the first few drops from one side of the spout go down the drain as I find it smoothens the taste out. I think this is an old italian barista trick from what I read, somewhere, a long time ago.
You might also like to have a watch of one of James Hoffmanns videos recently where he talks about crema.
He proposes that crema is not the be-all-end-all of espresso and that it can detract from the taste. Try scooping the crema off and trying the resultant shot, or stirring it through the espresso.