So far the only player whom we played Heavy-Medic tandem perfectly has been Spy. When I was a heavy Spy was taking perfect positions to defend himself from fire and I was trying to defend him in a first place. I usually carry sandwich as a secondary weapon and used to throw it to medic all the time. We were making a good tandem. In any case when I play medic, I usually use medigun when trying to break through enemy's defense and quick-fix when defending own base primarily because of fast healing.