Streamline limitations

Having been a lazy streamliner it's high time I work on the closest thing to a free lunch at our disposal. No excuses any more! I never fully appreciated what a huge disparity there can be b/t a lazy age grouper streamline and a great streamline. To the tune of a good 8 seconds per 100 on some very non-scientific field experiments side by side. Wow! Just the initial push off and streamline my poor form costs me nearly a full body length vs his amazing streamline by the time we both take our first stroke. This is a guy I have routinely beaten by a considerable margin in open water events over many years. Great learning experience getting whipped in the pool by a superior technician in my pal. W A N T to get better. What is more important for an old fart who has less than stellar flexibility? I can certainly get my hands overlapping with elbows quite close to narrow my frontal profile within the margin of my shoulders, but overall the hands will be down below my head. As in looking from the side my arms would be pointing a good 20 degrees down if my torso/legs are level with the surface of the water. Or.... Would I want to have my body line flat from head to toe, but sacrifice the narrow profile having to separate my hands and utilize a wider position? I'm thinking this wider Superman position would be the higher drag position and needs to go in the garbage bin? Just don't want to be practicing the wrong things as I'm committed to making the best streamline I can somewhere down the road. Any particular stretches I might focus on? Thanks.