Dex- Humalog and Novolog in general are 100% identical but some do say that btwn novolog and humolg, Novolog appears to be both stronger and quicker.
Regarding prebolusing by weds I usually bolus like 3 units prior heading to the smorgasbord take into account that most goodies are 30carbs at least if not more . Than after eating my portion I bolus for the missing carbs.
Diabetes is an Art, NOT a Science. You must master the control by skills and not by knowledge alone.