Sorry: Skyrim Perk Calculator - Plan the perks for your Skyrim character before spending them! is the basics. Shield Charge is when you pretty much don't have to worry about being overrun again, just keep enough Stamina to sheathe, and bulldoze through them, recast, and shoot them getting back up. When you have enough Conjuration (Inevitable) you can add Expert, and Summoner for Dremora Lord. You can also go on to Atromancy, Elemental Potency, and Twin Souls for even more infantry, but the gateway perks don't affect Dremora Lords. (I actually went Necromancy, but this is better.)
Normally, Storm Atronachs would be good extra firepower to shoot down dragons, but you're going to fast track the Main Questline to get the Targe anyway, and the very next Quest you get Dragonrend, so you probably won't need to. Jenassa does very well as a follower for this style, as you can keep them stunned while she covers you, or she can hold her own with Dual wield with your support fire. Even with you both holding a bottleneck, or corridor (The one with the Wiights in High Gate Ruins comes to mind) you bash, she slashes, and you're basically a short section of Phalanx. Just don't get surrounded out in the open, you should be fine.
I put it ALL in health. Magicka was pretty much handled by Vokun, and being Altmer. Stamina is just to bash your way out, and Wuld away (The targe is your backup) and the Bow doesn't need much Stamina unless you haven't learned to quickscope, and stay in Eagle Eye. (A lot of people abuse Steady hand, which I don't even use, and it guzzles Stamina.) I suggest the same, until you actually realise that you're a little low on Stamina, or to gear up for simulcasting Dremora Lord, then Twin Souls so you have to be abke to drop two of them, and still cast the bow. You're not doing Heavy Armor, so Stamina is even less of a problem, but Health is even more critical.
I don't do H/S/M proportions, over the 'net. What works for me won't work for you, because you're not going to play exactly the way i do. You're natuarally going to get hit more, or sprint less, or vicea versa anyway, and I always take it level by level. Whateve I need more, that's what I get, but there's a default dump stat, and in this one, it's probably Health.
Thanks a bunch everyone.
So getting the targe is part of the main questline? I can't just got grab it when I go to the fort to get bound bow? They seem relatively close together right?