If you have difficulties with control, you are doing something wrong.
Playing with the whole arm makes control MUCH easier, because the movements are now more "unified".
It seems you have understood something wrongly; and with all technical / motional things it's absolutely crucial to have personal supervision by a teacher. It's not transferable by words, but only by personal experience.
So, we here can say little regarding your problem; get a competent teacher.
And since you are rather old, chances are that you already have developed difficult-to-break habits that only can be altered with very competent, sensitive help.
Best Wishes,
Monk