Motion slowdown is, in my humble opinion, the optimum combination for slaying those high ATH/SPD press teams at D3.
A factor within motion offense is that it offers the best chances for getting opportunistic baskets, hence is why you never really want to load up on just 2 or 3 players, while fullcourt press (while creating more turnovers) is the worst for allowing opportunistic scores. So, while reducing the opponents chances for creating turnovers, the slowdown also increases your chances of offensive efficiency - of which, when set up properly, motion inherently offers the best chances for.
Sprinkle that in with things like your best players playing more minutes, the opponents higher chances of getting into foul trouble, etc., then you got a pretty good formula for exploiting the weaknesses of the fullcourt press.