My templarcher is going 2/1/2 mag/health/stam while leveling. I may change that up eventually, especially come late game where it is easy to cap mag/stam with gear. You do not need that much health if you are ranged and can avoid most damage with CC or simply watching what to dodge, etc. At least, in pve. If it's a pvp focus, I would dedicate to almost entirely health.

While leveling, I find a balance works pretty well. A magicka focus with bow will not break you if you use a lot of class skills in your build and it is especially nice for healing yourself or others.