Spell Tomes and Enchanting

I could find no credible sources about this, so I performed a completely unscientific experiment to figure this out:

I loaded up a low-level saved game and used Flame continuously until my magicka was exhausted, then took a screenshot of the skill screen. I then reloaded the game and used Flame in ~1 second bursts until my magicka ran out, and took another screenshot. I then compared the pixels in the screenshots using Paint, and determined that they had both advanced an equal number of pixels. This suggests that it's extremely likely that it doesn't matter if you cast with duration or frequency - you'll gain at the same rate.

In summary, there is most likely no difference.

Sort and simple answer is yes! My second character is based around this build. I am currently level 32 and I am quite enjoying it. I rarely use equilibrium as I rarely run out of magicka and when I do I have a loooot of potions from hoarding them around.

At the moment I am dual casting apprentice level destruction - and yes this more than enough to kill frost dragons. maybe it takes a few more hits but it staggers dragons (not Alduin) and I am waiting till my enchanting is 100 so I can make my destruction free and not waste anymore perks. I use rune spells and conjuration (fire, storm and dremora lord) regularly to give me a tactical advantage.

Early game I'd suggest having a follower but not really that necessary later on.

I used restoration perks to increase my magicka regen by 50% so I can use atronach stone. i use arch mage's robe, morokai's mask and self enchanted amulet and ring for giving more magicka+magicka regen. So I suggest doing college of winterhold quests asap. Right now I have around 430 magicka and 410 health.

Hope this answers your question though I am a month late :p

Edit:

I will put up my character build here and edit it every so often if it helps:

• level: 35 (atronach stone)
• Enchanting - lvl 100 (and I always use grand souls for enchanting my gear)
• Destruction - lvl 90
• conjuration ~ lvl 86
• alteration - lvl 33 (I am including this as this is the next skill I will try to develop)
• gear: orcish armor (destruction+alteration), ebony helmet (destruction+alteration), ring (destruction+conjuration), amulet (destruction+conjuration), ebony gauntlets (magicka+something nice). So this makes all my destruction cost 0 magicka.

I tested this at the last part of the main quest-line

from the point where you enter Skuldafn.

It works rather well, would work better with some (crowd) control spells eg. paralysis from alteration, or some illusion spells etc.