how will a locker behave up front?

Its not the same as cluchpack. If you get one wheel in the air with Truetrac you get 0 torque to the wheel on the ground. When you get one wheel with clutchpack LSD you get as much as pre-load is set. In winter time the difference is that with clutchpack even offcamber you can easily peel two wheels(if it is workign properly). With truetrac its much harder to do that and more often ends up to act like open diff.