The best way to land para on a mob is probably to use frost armor on someone who's getting hit, TBH. As for M. Acc from skill, I have no idea what the figure is, but it would have to be at best 2 skill to 1 M. Acc, and probably less.
The reason I suggested M. Acc gear over Summoning magic Skill gear is that there's not a great deal of pet/avatar M. Acc gear about, so I figure that if you put in the few pieces that there are, you can then probably still get 500 skill, which is quite likely to be a hard cap anyway.