You can't block and light attack at the same time.

first off, since you now have an ice staff, put it on your backbar and also slot elemental blockade. thats the skill which is necessary as tank with a staff. additionally you should choose, if your blocking on the ice staff bar should consume magicka or stamina (if it should consume magicka, make sure to not have the tri focus passive skilled).
now for the basics: you said you use a lot of light attacks and weave between skills. thats not bad, since light attacks provide a high uptime of the weapon enchants. tanks mostly use light attacks to proc the enchants, since dps wise their light attacks actually doesnt really matter. you said, that lot of tanks do not use them, thats because in some trials a lot of blocking is a must to survive. while blocking you cant do normal light attacks.
so what does matter for you: choose which resource will be drained by blocking on your staff bar, slot elemental blockade (this is very important to add effects like minor maim or roots (with an ice staff) or offbalance (with a lightning staff), also elemental blockade helps you proccing your weapon enchants, very important next patch, since it will proc the enchant from your staff then), learn when weaving light or heavy attacks is important (proccing enchants or restoring resources) and when you shouldnt weave, because you are in danger (then blocking or shielding up is important).