Round a Column of Numbers to a Specific List

Im sorry if im just being a nitpick at this point:

How do I alter the code so that it does the entire column? There's always going to be a different amount of column values with each spreadsheet im doing this to.

Can you integrate the desired numbers to be specified into the subroutine? It would look much better than having a random string of numbers laying around on the spreadsheet.

Edit: I got this fully functional minus the above alterations needed. Appreciate all the help thus far guys.