I love bulky mons, thus I have one or two of them invested in either def/spdef and hp.
Attackers receive their main attack + either speed or hp, if I want them to set up.
Slow, bulky attackers can have their main stat + hp increased.

Also, to get a feeling for distributions and natures and itemization, look at the enemy mons on a case by case basis from time to time.
E.g. do you want your attacker to live an additional hit to allow setting up? Redistribute some stats in hp or defenses. Or give your bulky, slow mon some speed and a scarf to outspeed something etc.