Any chance you can demo these boards? where you at? at most snowboard shops out here in CO you can pay an up front fee and ride as many boards as you like in a day.
Advice from other people on boards is pretty worthless, you are the expert when it comes to what works.
For what its worth, on the whole the most favoured board for all of my lady students has been either the bnice or bstreet by GNU. I have been amazed by the edge hold on early season ice by those boards even given terrible technique. If your set on the Jones I personally think the 46 would be best for your weight, but try it out.