Depends on which class you are going to rely on primarily. Are you going to use bows as an opener or rely on them when you are out of mana?
Sneaky type or cannon glass?
Too many possibilities.
Illusion and Archery makes good synergy. But so does Conjuration and Archery

As for stats, it would be safe to go 50/50 on them depending on diffuculty your playing at. But mage and archer are both ranged characters so i would lean on magicka more and ignore stamina totally.