I'm not sure that precision effects choice of target. Otherwise I agree with you on all your points
Another point, which follows from your advice but was not explicitly stated is: Do not ever put two mages in the same square.
Especially if one of those mages is an astral mage.
One thing that I like to do when placing mages is give each mage two bodygaurds (assuming the mage is size 2). They will stay near him in the same square and drop the probability of an arrow striking him to 1/3.