Magister kinda sucks as a Guild. They give all there stuff to this guy who sells it on Player Auctions under the name Big_Shag. So this guy Big_Dick...I mean Big_Shag sells this stuff for tons of money and cuts the Magister Guild leader in for a chunk of the loot, unbennounced to his Guild of course:)
Considering where these come from, I can't imagine anyone wearing these as shoulders. Well, unless their perticularly lazy (8th coldain prayer shawl has the equivelent of FT 2, and extends duration of spells, more int/wis, has saves, bonus HP and Mana. Honestly, it's alot of effort to get the shawl, but it's not like it's harder than getting to Vex Thal.) Maybe as arms, guess it would depend on the class.
btw, yes bonuses can take you above class limits, as long as that wouldn't go over 255.
I'm not totally sure, but I believe you can go past that classes cap, as long as you don't go past the overall hard cap of 255. Don't take my word for it, thou.